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|       ILLINOIS  STATE       I 

|        LABORATORY         | 
|    OF  NATURAL  HISTORY    1 

LIBRARY  | 


XI  E>  HAR.Y 

OF  THE. 

UNIVERSITY 

OF    ILLINOIS 


tWURAL  HISTORY   SURVEV 

550.5 

FI 
v.3,  cop.Ct. 


REMOTE  §T§rMJ3F 


*& 


Field  Columbian  Museum. 

Publication   i  29. 

Geological  Series.  Vol.  Ill,  No.  7. 


NOTES  ON  VARIOUS  MINERALS 
IN  THE  MUSEUM  COLLECTION 


By 


Oliver  Cummings  Farrington, 
Curator,  Department  of  Geology. 

AND 

Edwin  Ward  Tillotson,  Jr. 


Chicago,  U.  S.  A. 

December  i,   1908. 


LIBRARY 

UNIVERSITY  OF  ILLINOIS 

URBANA 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,    VOL.    III.      PLATE  XLIV. 


Realgar 

Golden  Gate  Mine 

Mercur,  Utah. 


Orpiment,  Mercur,  Utah. 


xh 


Realgar 
Mercur,  Utah. 


NOTES  ON   VARIOUS   MINERALS   IN   THE    MUSEUM 

COLLECTION 


BY  OLIVER  CUMMINGS   FARRINGTON   AND   EDWIN   WARD 
TILLOTSON,  JR. 


ANGLES1TE 

TINTIC   DISTRICT,   UTAH 
PLATES  xlv  and  xlvi 

An  especially  fine  series  of  crystallized  anglesite,  received  from 
Maynard  Bixby,  all  from  the  Tintic  District,  Utah,  and  chiefly  from 
Eureka,  afforded  material  for  a  study  of  the  crystal  habits  of  the 
mineral.  The  specimens  were  the  choicest  of  many  that  had  been 
collected  by  Mr.  Bixby,  and  are  probably,  therefore,  the  best  represen- 
tation of  the  anglesite  of  the  locality  that  has  yet  been  obtained. 

The  crystals  occur  almost  wholly  in  cavities  in  galena,  the  cavities 
as  a  rule  having  a  diameter  of  from  i  to  4  inches.  The  galena  shows 
a  coarse,  granular  structure  as  a  rule.  The  crystals  of  anglesite  occur- 
ring in  these  cavities  are  for  the  most  part  colorless,  but  some  are 
white  and  several  show  a  tinge  of  yellow,  in  some  cases  a  deep  canary 
yellow ;  others  exhibit  smoky  or  gray  shades.  As  a  rule  the  crystals 
are  nearly  transparent,  some  completely  so,  but  others  show  cloudings 
which  may  be  so  abundant  as  to  make  the  crystals  practically  opaque. 
As  is  usual  with  anglesite,  the  lustre  is  highly  adamantine  in  some 
specimens,  but  in  others  more  nearly  vitreous.  The  crystals  vary  in 
size  from  minute,  lining  druses,  to  one  having  a  length  of  4.5  centi- 
meters (1^  inches).  For  the  most  part  a  length  of  about  8  milli- 
meters may  be  considered  descriptive  of  the  size.  The  crystal  planes 
as  a  rule  are  well  developed  and  afford  fairly  good  measurements  with 
the  reflecting  goniometer.  Not  infrequently,  however,  the  surfaces  are 
more  or  less  uneven  so  that  only  broken  reflections  are  obtained. 
The  planes  of  the  different  forms  are  as  a  rule  uniform  in  lustre  and 
character  of  surface,  with  the  exception  of  the  macropinacoid,  a  (100), 
which  is  nearly  always  characterized  by  being  striated  in  the  direction 
of  the  vertical  axis.     It  can  usually  be  recognized  by  the  naked  eye 

131 


132  Field  Columbian  Museum — Geology,  Vol.  III. 

by  this  peculiarity  and  thus  the  orientation  of  the  crystal  is  much 
facilitated.  These  striations  are  probably  the  result  of  oscillation  of 
the  plane  a  (100)  with  prismatic  planes,  and  in  some  crystals,  as 
shown  in  Fig.  3,  PI.  XLVI,  this  is  obviously  the  case. 

As  is  usual  with  anglesite,  the  crystals  exhibit  a  variety  of  habits, 
no  single  habit  predominating.  The  habits  noted  may  be  described 
as  tabular,  prismatic,  and  pyramidal.  Of  these  perhaps  the  most 
striking  and  unusual  to  anglesite  is  the  tabular  one.  It  is  produced 
by  a  pronounced  development  of  the  basal  planes  uniting  with  a  short 
unit  prism.  Figs.  2  and  3,  PI.  XLV,  showing  crystals  taken  from 
specimens  having  the  Museum  Numbers  M  9579  and  7293,  illustrate 
the  habit.  Crystals  of  this  type  may  be  simple  or  highly  modified. 
In  some  the  prism  becomes  longer  in  the  direction  of  the  vertical 
axis,  as  shown  in  Fig.  3,  PI.  XLV.  Crystals  of  this  type  are  usually 
attached  by  one  of  the  planes  of  the  unit  prism  so  that  their  orienta- 
tion is  not  always  obvious  at  a  glance. 

Prismatic  habits  are  common  and,  as  is  usual  with  anglesite,  the 
habit  may  be  produced  by  elongation  in  the  direction  of  either  of  the 
axes.  Crystals  elongated  in  the  direction  of  the  vertical  axis  are 
illustrated  in  Fig.  4,  PI.  XLV  (Mus.  No.  M  9590)  and  Fig.  1,  PL  XLVI 
(Mus.  No.  M  9586).  Of  these  No.  M  9590  is  from  the  Bullion  Beck 
mine.  It  exhibits  the  peculiarity  of  having  the  prism  m  (no)  at 
one  end  of  the  crystal  and  the  prism  8  (230)  at  the  other.  As  illus- 
trated in  the  figures,  the  crystals  of  the  vertically  elongated  prismatic 
habit  may  have  pointed  or  blunt  terminations.  The  blunt  termina- 
tion is  produced  by  broad  development  of  the  basal  plane  and  gives  an 
especially  characteristic  form  (Fig.  1,  PI.  XLVI).  Crystals  elongated 
in  the  direction  of  the  brachy-axis  are  illustrated  by  Fig.  2,  PL  XLVI 
(Mus.  No.  M  9587).  Crystals  of  this  type  are  inclined  to  stoutness. 
They  are  semi-transparent  and  have  the  planes  well  developed. 
The  finest  crystal  of  the  whole  collection  exhibits  this  habit,  the  elon- 
gation in  the  direction  of  the  brachy-axis  being,  however,  less  than 
shown  in  the  figure  of  the  type.  This  crystal  has  a  length  of  2  centi- 
meters in  the  direction  of  the  vertical  axis  and  1 . 5  centimeters  in  the 
direction  of  the  macro-axis.  It  is  perfectly  transparent  and  colorless. 
Another  superb  crystal  of  this  habit  has  a  well-marked  canary  yellow 
color.  It  is  about  three-fourths  the  size  of  the  one  previously  men- 
tioned. 

Fig.  3,  PL  XLVI  (Mus.  No.  M  9582)  shows  a  crystal  form  in  which 
the  elongation  occurs  in  the  direction  of  the  macro-axis.  Crystals  of 
this  type  are  as  a  rule  small,  having  a  maximum  length  of  about  1.5 


Dec,  1908.  Mineralogical  Notes  133 

centimeters,  and  possess  a  yellow  tinge.  They  may  be  described  as 
having  a  wedge-shaped  form,  this  being  chiefly  produced  by  the 
development  of  the  prism  M  (410). 

Another  prismatic  habit  is  characterized  by  a  normally  developed 
unit  prism  combined  with  extended  basal  and  macropinacoids. 
Several  pyramids  also  usually  round  the  edge  between  the  basal  plane 
and  prism.  These  crystals  are  as  a  rule  transparent  and  colorless 
and  rather  small  in  size,  their  length  in  the  direction  of  the  vertical 
axis  being  about  4  millimeters,  and  in  the  direction  of  the  macro- 
axis,  about  7  millimeters.  Fig.  1,  PI.  XLV  (Mus.  No.  M  9573)  illus- 
trates this  habit. 

The  only  remaining  habit  to  be  noted  is  a  pyramidal  one.  Crys- 
tals of  this  habit  are  as  a  rule  of  simple  development  and  are  com- 
posed principally  of  the  pyramid  y  (122)  with  minute  basal  planes  and 
macro  or  brachydomes.  One  crystal  of  this  type  also  shows  small 
planes  of  the  unit  prism.  These  crystals  have  average  lengths  in  the 
direction  of  the  vertical  axis  of  from  5  to  10  millimeters.  On  one 
specimen  (Mus.  No.  M  9569)  represented  in  Fig.  4,  PL  XLVT,  the 
crystals  have  a  milk-white  color,  while  those  of  another  specimen 
(Mus.  No.  M  9576)  represented  in  Fig.  5,  PI.  XVLI,  are  more  nearly 
transparent  and  dark  colored.  The  occurrence  of  the  macrodome 
on  one  and  brachydome  on  the  other  is  also  notable.  One  speci- 
men (Mus.  No.  M  9677)  exhibits  a  single  large  crystal  possessing  a 
pyramidal  habit,  but  owing  to  the  rounded  nature  of  the  planes  the 
symbol  could  not  be  determined.  The  crystal  is  4.5  centimeters  in 
length,  partially  opaque,  and  of  a  dark  yellow  color.  Another  habit 
of  occasional  occurrence  is  produced  by  a  combination  of  a  pyramid 
and  prism  in  about  equal  proportions.  Crystals  of  this  type  (Mus. 
No.  M  9581)  are  illustrated  in  Fig.  6,  PI.  XLVI.  They  are  not  as  a 
rule  doubly  terminated,  but  are  so  occasionally.  Generally  they  are 
small,  about  .7  of  a  centimeter  being  an  average  length.  These  crys- 
tals are  also  as  a  rule  transparent  and  colorless. 

A  total  list  of  the  forms  observed  on  the  Eureka  anglesites  is  as 
follows : 

(230)  r  (112) 

(120)  z  (111) 

(011)  r   (221) 

(102)  p  (324) 

(104)  y  (122) 

ft  (124) 


a     (100) 

d 

b     (010) 

n 

c     (001) 

0 

m  (no) 

d 

M  (410) 

I 

134  Field  Columbian  Museum  —  Geology,  Vol.  III. 

BARITE 
CARTERSVILLE,  GEORGIA 

FIGS.  1-3,  PLATE  XLVII 

A  fine  suite  of  barite  crystals  from  the  above  locality  was  pre- 
sented to  the  Museum  in  the  fall  of  1902  by  Prof.  S.  W.  McCallie,  the 
present  State  Geologist  of  Georgia.  The  specimens  have  the  Museum 
Nos.  M  7172-7235.  While  the  occurrence  of  barite  at  the  Carters- 
ville  locality  has  been  described  before,  its  crystallographic  characters 
do  not  seem  to  have  been  given  in  detail.  It  seemed,  therefore,  desir- 
able to  make  a  crystallographic  study  of  this  suite. 

The  manner  of  occurrence  of  the  barite  has  been  fully  described 
by  Hayes*  who  states  that  it  accompanies  bodies  of  ocher  occurring 
in  the  Cambrian  quartzite  of  the  region,  the  ocher  being  mined  ex- 
tensively for  economic  purposes.  Numerous  passages  and  cavities 
penetrating  the  quartzite  and  ocher  are  lined,  Hayes  states,  in  the 
case  of  the  smaller  cavities  with  a  crust  of  small  quartz  crystals, 
while  the  larger  ones  frequently  contain  beautiful  crystals  of  barite, 
which  according  to  Hayes,  "were  probably  deposited  after  the  con- 
ditions favorable  for  the  solution  of  silica  and  the  deposition  of  ocher 
had  passed."  Hayes  also  says,  "Groups  of  acicular  crystals  of  this 
mineral  several  inches  in  length  are  not  uncommon.  It  also  occurs 
in  white  granular  veins.  The  barite  is  called  'flowers  of  ocher'  by  the 
miners.  It  remains  in  the  residual  soil  which  covers  the  quartzite 
outcrops  and  affords  the  best  means  of  tracing  the  ocher  deposits. 
It  is  found  at  numerous  points  on  the  low  quartzite  ridge  north  and 
south  of  the  Etowah  river ;  and  prospecting  at  these  points  has  never 
failed  to  reveal  more  or  less  extensive  deposits  of  ocher." 

The  crystals  in  possession  of  the  Museum  form,  as  a  rule,  interpen- 
etrating groups  or  clusters,  some  of  which  are  nearly  a  foot  in  length. 
The  individuals  of  the  group  are  often  largely  made  up  of  aggregates 
having  the  macro-axis  in  common.  These  combine  so  as  to  produce 
a  polysynthetic  individual  with  serrated  edges.  The  crystals  are 
transparent  to  translucent  except  where  the  ocher  enters  into  their 
substance  in  quantity,  in  which  case  it  renders  them  opaque.  The 
color  of  the  transparent  crystals  is  a  delicate  greenish-blue;  but  the 
crystals  that  are  opaque  partake  to  a  greater  or  less  degree  of  the 
yellowish-brown  color  of  the  ocher. 

*  Geological  Relations  of  the  Iron  Ores  in  the  Cartersville  District,  Georgia,  Trans.  Amer. 
Inst.  Mining  Engineers,  1900,  Vol.  XXX,  p.  418. 


Dec,  1908.  Mineralogical  Notes  135 

The  habit  of  the  simple  crystals  is  uniformly  tabular  with  respect 
to  c  (100).  They  are  usually  also  slightly  lengthened  in  the  direction 
of  the  macro-axis.  The  planes  are  bright  and  sharply  outlined  and 
give  good  signals  with  the  reflecting  goniometer.  In  length,  in 
the  direction  of  the  brachy-axis,  the  individuals  vary  from  1  to  2.5 
centimeters.  Their  average  thickness  is  about  5  millimeters.  They 
are  rarely  highly  modified.  They  are  usually  made  up  chiefly  of 
three  pinacoids  and  the  unit  prism,  pyramid  and  brachydome. 
Striations  parallel  with  the  edge  m  a  usually  characterize  the  prismatic 
zone  except  for  planes  of  m,  a  and  b,  which  are  smooth  and  bright. 
Fig.  1,  PI.  XLVII  shows  the  usual  type.  The  development  of  the 
prism  is,  however,  not  as  a  rule  as  well-defined  as  indicated  in  the 
figure,  the  zone  from  a  to  m  being  often  considerably  rounded  and 
showing  no  well-marked  planes.  There  may  also  occur  a  rounding 
of  this  sort  between  m  and  b.  Such  rounding  is,  in  fact,  quite  char- 
acteristic. Some  crystals  are  somewhat  more  highly  modified  than  the 
above.  These  show  as  a  rule  several  pyramids  and  an  increased  num- 
ber of  prisms.  Figure  2,  Plate  XLVII  (Mus.  No.  M  7197)  illustrates 
such  a  crystal.  This  crystal  was  about  1  sq.  cm,  in  area  and  2  mm. 
thick. 

Perhaps  the  most  interesting  type  presented  by  these  barites  is 
that  already  mentioned  in  which  numbers  of  smaller  crystals  com- 
bine to  produce  a  crystal  of  different  habit.  The  most  common  form 
of  these  is  illustrated  in  Fig.  3,  PI.  XLVII.  Here  small  primary  crys- 
tals, chiefly  made  up  of  the  basal  plane  and  unit  prism,  have  grown 
together  in  parallel  position  to  form  a  crystal  of  tabular  habit  which 
shows  essentially  the  planes  c  (001),  a  (100),  and  o  (on).  Here,  there- 
fore, the  crystallizing  force  controlled  the  arrangement  and  situation  of 
the  individual  crystals  as  well  as  that  of  the  molecules  in  the  crystals 
themselves.  The  crystal  here  illustrated  is  not  doubly  terminated  in 
the  direction  of  the  a  axis,  but  in  all  other  directions  is  fully  developed. 
The  size  of  these  large  polysynthetic  crystals  is  from  3  to  6  centimeters 
in  the  direction  of  the  a  axis,  and  in  the  direction  of  the  c  axis  about 
one-fourth  of  this.  Groups  of  diverging  crystals  which  have  no  ap- 
parent regularity,  also  occur  among  the  specimens. 

The  total  forms  observed  on  the  Cartersville  barites  and  some  of 
the  measurements  obtained  are  as  follows: 

c   (°QI)  X  (x3o)  /  (n3) 


a  (100) 

\   (210) 

q  ("4) 

m  (no) 

0  (on) 

y  (122) 

n  (120) 

z  (in) 

136 


Field  Columbian  Museum — Geology,  Vol.  III. 


m 

A 

m 

\ 

A 

X' 

b 

A 

n 

b 

A 

X 

0 

A 

0 

c 

A 

z 

c 

A 

f 

c 

A 

q 

c 

A 

y 

0 

A 

y 

(no] 

>    A    0 

(210] 

1     A     ( 

(010] 

1    A     ( 

(010 

)    A     ( 

(on] 

A     ( 

(00 1  ] 

1     A     ( 

(OOI> 

A     ( 

(00 1, 

>     A     ( 

(001] 

A     ( 

(on 

>     A     ( 

(ilo) 

(2I0) 
(120) 

(13°) 

(oil) 

(III) 

(113) 
(114) 

(122) 
(122) 


Observed 

Calculated 

78°   25' 

78°   22' 

44°   27' 

44°   21' 

3i°  23' 

31°  3l' 

22°  17' 

22°    14' 

74°  27' 

74°  34' 

64°  50' 

64°  19' 

34°  40' 

34°  43' 

27°   34' 

27°  28' 

57°  10' 

57°     1' 

26°  15' 

26°     1' 

BERTRAND1TE 

ALBANY,   MAINE 

FIGS.  4-5,  PLATE  XLVII 

In  the  summer  of  1902,  Mr.  C.  C.  Spratt,  at  that  time  a  resident  of 
North  Bridgton,  Maine,  submitted  to  one  of  the  authors  some  hand 
specimens  showing  small,  colorless  crystals,  which  proved  on  examina- 
tion of  their  blowpipe  characters  to  be  bertrandite.  Mr.  Spratt 
kindly  indicated  the  locality  from  which  the  specimens  were  obtained 
and  this  was  later  visited  by  one  of  the  authors.  The  locality  is  an 
area  of  coarse  pegmatite  in  the  northern  part  of  the  town  of  Albany, 
Maine.  The  pegmatite  exhibits  the  usual  coarse  crystals  of  quartz, 
feldspar,  tourmaline,  mica,  and  beryl  and  has  been  worked  to  some 
extent  to  obtain  the  two  latter  minerals  for  economic  purposes.  The 
bertrandite  was  nowhere  found  to  be  abundant,  but  by  close  searching 
could  occasionally  be  obtained.  It  occurs  in  single  or  grouped  crys- 
tals implanted  upon  quartz  or  lining  cavities  one  or  two  inches  in 
diameter.  In  one  of  these  cavities  a  considerably  corroded  piece  of 
colorless  beryl  was  found  suggesting  that  the  bertrandite  may  have 
been  derived  from  alteration  of  the  beryl.  The  crystals  of  bertrandite 
obtained  (Mus.  No.  M  6969)  are  for  the  most  part  colorless  to  pale 
white  and  transparent  to  translucent.  Some  are  covered  with  a  rusty 
coating  which  readily  dissolves  in  hydrochloric  acid.  The  crystals  all 
show  a  tabular  habit  produced  by  extensive  development  of  the  basal 
planes.  In  habit  they  thus  resemble  the  crystals  of  Mt.  Pisek  and 
Mt.  Antero  rather  than  those  described  by  Penfield  *  from  Stoneham, 
although  the  latter  locality  is  near  Albany.     The  largest  crystal  of 

*  Am.  Jour.  Sci.,  1889,  3,  37,  p.  214. 


Dec,  1908.  Mineralogical  Notes  137 

the  Albany  material  in  the  Museum  is  10  mm.  long,  10  mm.  wide  and 
2  mm.  thick.  Some  crystals  seen  must  have  been  even  larger  than 
this  but  they  were  broken  in  excavating.  The  crystals  in  cavities 
are  as  a  rule  smaller  than  those  attached  to  quartz,  their  average  size 
being  3x3x1  mm.  The  attachment  of  all  the  crystals  is  always 
along  an  edge  parallel  with  the  vertical  axis.  They  thus  rarely  show 
more  than  half  the  faces  belonging  to  the  prismatic  zone.  Their  out- 
line tends  to  be  rectangular  or  hexagonal,  according  as  the  lateral  pin- 
acoids  or  the  prisms  predominate.  The  orientation  adopted  for  the 
crystals  for  measurement  was  determined  by  the  basal  plane  and  by  a 
pinacoidal  cleavage  normal  to  this  which  was  regarded  as  that  of  the 
brachypinacoid,  b  (010).  The  distinctive  characters  of  the  base  are 
its  pearly  luster  and  striations  ||  to  a  (100).  In  addition  to  the  cleav- 
age ||  to  b  (010),  a  prismatic  cleavage  giving  angles  of  nearly  6o°  was 
occasionally  observed.  The  faces  of  the  crystals  on  casual  inspection 
appear  bright  and  would  seem  to  be  well  suited  for  measurement, 
but  on  closer  examination  their  surfaces  are  found  as  is  usual  with 
bertrandite  to  be  uneven  and  to  give  elongated  reflections.  This  is 
especially  true  in  the  prismatic  zone,  where  nearly  all  the  measure- 
ments give  variations  between  2°  and  30.  By  taking  the  mean  of 
these,  however,  values  were  obtained  which  served  for  identifying  the 
faces.  The  crystals  are  not  highly  modified,  only  six  forms  being 
observed,  as  follows: 

c  (001)  a     (100)  /  (130) 

b  (010)  m  (no)  */  (203) 

Of  these  /  (203)  is  new  to  bertrandite,  its  determination  being  based 
on  the  measurement  caI  =  (001)  a  (203)  =33°  56'.  The  calculated 
angle  for  this  form,  using  the  axial  ratios  of  Penfield*  is  340  59'  or 
using  those  of  Urbaf  is  340  48'.  While  the  agreement  of  measured 
and  calculated  values  for  this  form  is  not  as  close  as  could  be  desired 
it  is  all  that  can  be  expected  when  the  imperfections  of  the  planes  are 
considered.  The  measurements  upon  which  the  determinations  of  the 
prisms  were  based  are  as  follows,  these  being  shown  with  the  values 
calculated  from  both  Penfield's  and  Urba's  ratios: 

Observed  Calculated 

Penfield         Urba 
m   a    m"      =    (no)    A    (1I0)  =     580  52'     59°  16'     59°  21' 

f     A  f         =    (130)    A    (T30)  =     6i°   12'     6o°  44'     6o°  39' 

Cleavage  a  cleavage  =  (1 10)  a  (010)    =     6o°  16'     6o°  22'     6o°  19' 

•Am.  Jour.  Sci.,  1880,  3,  37,  p.  215.  tZs.  Zr.  1880,  15,  p.  194. 


138  Field  Columbian  Museum  —  Geology,  Vol.  III. 

There  is  little  variation  in  the  development  of  the  crystals,  the 
principal  differences  being  in  the  development  of  the  macropinacoid 
a  (100).  When  this  is  extended,  as  shown  in  Fig.  4,  PL  XLVII, 
the  crystals  have  a  generally  rectangular  outline ;  when  it  is  developed 
about  equally  with  the  prisms,  the  crystals  have  an  apparently  hex- 
agonal outline  if,  as  is  usually  the  case,  only  half  of  the  crystal  is  pres- 
ent. Again  the  unit  prism  m  (no)  may  be  wanting  entirely.  If  so, 
the  crystal  is  usually  elongated  in  the  direction  of  the  macro-axis 
and  attached  by  the  brachypinacoid  b  (010)  so  that  the  appearance 
illustrated  in  Fig.  5,  PI.  XLVII  is  obtained.  This  drawing  is  made 
with  b  (010)  in  front  in  order  to  show  the  characteristic  appearance. 
The  form  /  (2°3)>  as  illustrated  in  the  figures,  occurs  at  only  one  end  of 
the  vertical  axis.  The  absence  of  a  corresponding  plane  indicates 
hemimorphism  in  the  direction  of  the  vertical  axis  such  as  was  noted 
by  Penfield.*  The  edge  opposite  to  /  (203)  produced  by  the  junction 
of  c  (00T)  and  a  (100)  and  that  upon  which  a  plane  corresponding  to 
/  would  normally  appear  if  the  crystal  were  holomorphic,  is  never 
sharp,  but  grades  irregularly  toward  the  center  of  the  crystal  by  suc- 
cessive overlying  lamellae,  all  of  which  have  irregular  edges.  Such 
indications  of  lamellar  structure  suggest  twinning  similar  to  that 
noted  by  Penfield  on  crystals  from  Mt.  Antero,f  but  study  of  cross- 
sections  of  the  crystals  in  polarized  light  gives  no  evidence  to  support 
such  a  view.  Extinction  in  polarized  light  occurs  parallel  to  the  pina- 
coidal  cleavage  of  the  crystals,  thus  affording  additional  proof  of  the 
orthorhombic  crystallization  of  the  mineral.  On  slight  heating  the 
crystals  become  strongly  electric  so  that  they  pick  up  pieces  of  paper. 
Before  the  blowpipe  they  exfoliate  slightly  and  when  heated  in  the 
closed  tube  decrepitate.  The  other  blowpipe  characters  observed 
were  similar  to  those  which  have  been  mentioned  by  previous  ob- 
servers. 


CALAMINE 

LEADV1LLE,   COLORADO 

Among  specimens  received  by  the  Museum  from  the  World's 
Columbian  Exposition,  a  series  of  ores  from  the  Maid  of  Erin  mine, 
Leadville,  Colorado,  contained  an  ocherous  substance  thickly  coated 
with  long,  slender  crystals.  These  crystals  proved  on  examination 
by  means  of  a  blow-pipe  to  be  calamine.  The  occurrence  seems 
not  to  have  been  hitherto  described,  although   Pratt  has  given  an 

*  Loc.  cit.  t  Loc.  cit. 


Dec,  1908. 


MlNERALOGICAL   NOTES 


139 


account  of  calamine,*  of  a  habit  quite  similar  to  the  above  and 
also  from  a  Maid  of  Erin  mine.  The  occurrence  described  by  Pratt 
is,  however,  in  Clear  Creek  Co.,  Colorado,  while  the 
locality  here  represented  is  in  Lake  Co.  As  the  crys- 
tals prove  upon  examination  to  exhibit  a  development 
somewhat  different  from  that  described  by  Pratt, 
there  seems  little  doubt  that  they  represent  a  separate 
occurrence.  Inquiry  by  the  writer  of  the  company 
now  operating  the  mine  from  which  the  Leadville 
calamine  was  stated  to  have  come,  elicited  the  infor- 
mation that  some  of  the  v/orkmen  thought  that  such 
crystals  had  been  obtained  in  earlier  operations  at 
the  mine  but  none  was  being  found  at  the  present 
time.  The  company  also  forwarded  a  specimen  quite 
similar  to  the  one  above  mentioned,  with  the  informa- 
tion that  it  had  been  found  at  the  El  Paso  mine 
adjoining. 

Like  the  Clear  Creek  Co.  calamine,  the  Leadville 
crystals  are  tabular  with  respect  to  b  (010)  and  con- 
siderably striated  in  the  prismatic  zone.  They  are, 
however,  differently  terminated.  Most  commonly 
the  termination  is  the  unit  macrodome  5  (101). 
Occasionally,  however,  the  steeper  dome  t  (301)  is  to 
be  seen  and  the  unit  brachydome  probably  also  occurs  although  this 
could  not  be  verified.  The  usual  appearance  of  the  crystals  is  illus- 
trated in  the  accompanying  Fig.  1.  Occasionally  there  is  a  larger 
development  of  the  prism,  giving  a  stouter  form.  The  crystals  tend 
to  form  groups  which  are  partly  radiated  and  partly  joined  by  the 
brachy-pinacoid.  No  doubly  terminated  crystals  were  found,  so 
that  no  opportunity  was  afforded  for  a  study  of  the  hemimorphic  char- 
acters of  this  mineral.  Gentle  heating  causes  the  crystals  to  become 
strongly  electric.  The  character  of  the  electricity  developed  by  such 
heating  was  tested  in  the  following  manner :  Numerous  crystals  were 
suspended  by  silk  threads  and  after  heating,  glass  rods  electrified  by 
silk  or  sealing  wax  excited  by  flannel  were  brought  near.  In  every 
case  the  positively  electrified  substance,  i.  e.,  the  glass,  attracted  the 
terminated  end  of  the  crystal  and  the  negatively  electrified,  the  broken 
end.  The  average  length  of  the  crystals  is  about  10  mm.  They  are 
transparent  to  translucent  and  colorless  to  white.  The  faces  best 
suited  for  measurement   are  the  macrodomes,  an  especially  sharp 

*  Am.  Jour.  Sci.,  1894,  3,  48,  p.  213. 


Fig. 


Calamine. 


Measured 

Calculated 

29°  53' 

29°  57' 

62°  54' 

62°  46' 

75°  35' 

76°     9' 

52°  20' 

5i°  55' 

140  Field  Columbian  Museum — Geology,  Vol.  III. 

measurement  of  t  (301)  on  s  (101)  having  been  secured  on  one  crystal. 
The  striations  in  the  prismatic  zone  make  measurements  there  unsatis- 
factory although  results  of  sufficient  accuracy  for  the  identification 
of  the  planes  were  secured.  The  following  are  some  of  the  measure- 
ments obtained : 


t  A  S         =  (301)  A  (ioi)  = 

5  A  S'       =  (ioi)  A  (Toi)  = 

m  a  tn™  =  (no)  a  (ilo)  = 

m  a  b       =  (no)  a  (010)  = 


CALCITE 
JOPLIN  DISTRICT,   MISSOURI 

PLATE  XLVIII  AND  FIG.  2,  PLATE  XLIX 

A  number  of  crystallized  specimens  of  calcite  from  the  Joplin  Dis- 
trict, Missouri,  received  for  the  most  part  from  Maynard  Bixby, 
present  features  hitherto  undescribed.  '  Most  of  the  specimens  are 
twin  crystals.  The  specimen  bearing  the  Museum  No.  M  8695  and 
shown  in  Fig.  2,  PI.  XLVIII,  is  from  the  Cuban  mine,  Joplin.  The 
twinning  plane  is  e  (01I2)  and  the  crystal  shows  its  greatest  elongation 
in  the  direction  of  this  plane.  The  length  in  this  direction  is  11  cm. 
(4X  inches),  while  at  right  angles  to  this  plane  it  is  only  about  half 
as  long  (5  cm.).  The  form  of  the  twin  is  roughly  prismatic,  the  sides 
of  the  prism  being  planes  of  the  unit  rhombohedron  r  (ioli)  and  the 
scalenohedron  S3!  (5 161).*  At  one  end  the  crystal  was  attached,  and 
here  it  shows  only  the  cleavage  rhombohedrons,  but  at  the  other  end 
occur  a  re-entrant  angle  and  a  number  of  modifying  forms.  The  latter 
forms  are  the  rare  scalenohedrons  enumerated  below.  All  are  about 
equally  developed.  The  substance  of  the  twin  is  white  and  opaque 
in  the  interior  and  yellowish  and  nearly  transparent  on  the  exterior. 
The  boundary  between  these  two  portions  is  rather  distinctly  marked, 
the  thickness  of  the  exterior  portion  being  about  5  mm.  The  planes 
of  the  crystal  have  brilliant,  flat  surfaces  as  a  rule,  but  the  larger  ones 
are  more  or  less  undulating  both  as  to  surfaces  and  edges.     Measure- 

♦Goldschmidt's  letter.  One  of  the  authors  has  elsewhere  (Pub.  Field  Col.  Mus.  Geol.  Ser.  Vol. 
I.,  p.  239)  given  reasons  for  combining  the  use  of  Dana's  and  Goldschmidt's  letters.  The  two 
kinds  of  letters  can  be  distinguished  by  remembering  that  Goldschmidt's  letters  are  followed  by 
dots. 


Dec,  1908.  Mineralogical  Notes  141 

merits  were  made  by  contact.     The  forms  determined  and  measure- 
ments obtained  are  as  follows: 


r(io!i)  +  R 

g3:(5iBi)+4Rt 

A(23S2)—  £R5 

/a(549i)  +  Rq 

G:(72Ss)  +  R| 

/.■(5273)  +  R3 

0(1235)— ^R3 

Observed     Calculated 

A    A    A'    = 

(23S2) 

A    (2532) 

400           420    14' 

r     a    A      - 

(ion) 

A     (23S2)            = 

36°          35°   45' 

t*       A    !>■'        = 

(54Si) 

A    (5gii) 

66°         66°  43' 

S3!    A    Si"   - 

(5i5i) 

A    (IS61) 

1360       1330  19' 

r      A    »i     - 

(10I1) 

A     (5l8l) 

36°         35°  54' 

Z       A    Z*        = 

(1235) 

a  a3^5) 

37°         35°  16 

G:   a   G:-   - 

(72S5) 

A     (9275) 

21°              20°    44' 

r*    A   G:     ^ 

(oln) 

A    (7925) 

92°3o'    92°  31' 

r      a   ."■       = 

(ioli) 

A     (54Sl) 

44°          44°  11' 

f    A   /:      - 

Coin) 

A     (5273) 

98°          99°   14' 

A  calcite  twin  bearing  the  Museum  No.  M  8692  is  shown  in  Fig.  1, 
PI.  XLVIII.  This  is  from  the  Crystal  Palace  mine,  Central  City,  Mis- 
souri. The  twinning  plane  is  c  (0001).  The  dominant  forms  are  the 
rare  rhombohedron  ^-(0533)  and  e  (01T2).  These  produce  an  approxi- 
mately spheroidal  twin,  but  only  about  half  the  spheroid  is  present  in 
this  specimen.  The  halving  is  due  to  the  manner  of  growth  from  the 
attachment.  The  twin  is  complete  in  a  polar  direction,  but  incom- 
plete equatorially.  The  length  of  the  polar  diameter  is  5.5  cm. 
The  substance  of  the  twin  is  wine-yellow,  and  transparent.  All  of 
the  planes,  however,  with  the  exception  of  those  of  the  rhombo- 
hedron e  (01T2),  are  coated  with  a  thin,  firmly  adhering  layer  of  iron 
oxide,  chocolate  brown  in  color.  The  planes  of  e  are  striated,  as 
represented  in  the  drawing,  and  as  also  represented  there  unite  with 
those  of  u-  by  a  curved  edge.  The  common  forms  v  and  M  modify 
the  dominant  forms.  The  twin  is  thus  made  up  of  three  rhombo- 
hedrons,  two  of  which  are  negative  and  one  positive,  and  the  scale- 
nohedron  v.  Of  the  rhombohedrons,  o.  (0533)  seems  to  have  been 
first  noted  by  Thurling  *.who,  however,  gave  it  no  letter.  Whitlock.f 
who  observed  it  on  calcite  from  West  Paterson,  N.  J.,  gave  it  the 
letter  here  employed. 

The  measurements  which  were  made  on  the  specimen  were 
by  contact,  but  the  planes  were  so  well  marked  that  there  seems 

*  Neues  Jb.  Beil.  Bd.,  1886,  4,  p.  380. 
t  Am.  Jour.  Sci.,  1007,  (4),  24,  p.  427. 


e 

A    e'      = 

(OI12) 

A 

(I012) 

v. 

A    V.'     = 

(0533) 

A 

(5053) 

M 

A    v.      = 

(4oii) 

A 

(OS33) 

V 

A    </       = 

(2l3l) 

A 

(23H) 

M 

aM  )   = 

tixnn    i 

(40II) 

A 

(40I1) 

45" 

3' 

95° 

26' 

57° 

12' 

75° 

22' 

280 

26' 

142  Field  Columbian  Museum  —  Geology,  Vol.  III. 

little  doubt  of  their  accuracy.      The  forms  and  measurements  are 
as  follows: 

e(oil2)-£R      v.  (o5S3)-|R         M(4o3i)  +  4R        tj(2i3i)+R3 

Observed         Calculated 

460 

95° 

57° 

73° 

290  10' 

The  specimen  bearing  Museum  No.  M  8696,  and  shown  in  Fig.  2, 
PI.  XLIX,  exhibits  a  habit  resembling  that  described  by  Sterrett* 
as  presented  by  twins  from  the  Maybell  mine,  North  Empire,  Kan- 
sas. The  Museum  specimen  is  from  the  Blackberry  mine,  Joplin. 
It  lacks  the  amethystine  color  characteristic  of  the  Maybell  mine 
twins,  being  colorless  and  transparent  except  for  small  internal 
reflections  and  inclusions.  Neither  is  the  Blackberry  mine  twin 
characterized  by  large  size  as  are  the  majority  of  the  Maybell 
mine  twins.  The  greatest  length  of  the  specimen  here  described  is 
along  the  twinning  plane  in  the  direction  of  the  edge  e  f,  and  is  8  cm. 
Normal  to  this  in  the  same  plane  the  length  is  4  cm.,  and  normal  to 
the  plane  the  length  is  2  cm. 

Like  the  Maybell  mine  twins  this  twin  exhibits  a  prismatic  form 
produced  by  prominence  of  the  planes  e  and  t.  One  end  of  the  prism 
terminates  in  a  re-entrant  angle  with  modifying  planes,  while  the 
other  end  was  attached  and  exhibits  the  cleavage  rhombohedrons  of 
the  two  individuals,  forming  a  salient  angle.  Aside  from  this  occur- 
rence of  the  unit  rhombohedron  it  does  not  appear  on  the  twin  although 
on  the  Maybell  mine  twins  it  is  prominent.  Two  scalenohedrons 
occur  on  the  re-entrant  angle  of  the  twin,  neither  of  which  is  repre- 
sented in  the  Maybell  mine  twins.  These  are  E  (4136)  and  a  form 
new  to  calcite,  v:  (1 1.4.15.3).!  Two  rhombohedrons,  which  are  the  com- 
mon forms,  /  and  M,  round  the  edge  between  e  and  E.  The  rhom- 
bohedron e  as  will  be  noted  by  the  figure,  is  the  dominant  form  of  the 
twin  and  is  also  the  twinning  plane.  The  common  scalenohedron  v 
which  does  not  occur  at  all  on  the  Maybell  mine  twins,  occurs  in  this 
twin  along  the  edge  on  which  the  individuals  meet. 

The  planes  of  the  crystal  are  for  the  most  part  brilliant  and  have 
sharp  edges.     The  scalenohedron  E  however,  is  striated.     Owing  to 

*  Am.  Jour.  Sci.,  1904.  41,8,  p.  73-76. 

t  The  authors  are  indebted  to  Dr.  Palache  for  designating  this  letter. 


Dec,  1908. 


MlNERALOGICAL   NOTES 


143 


the  size  of  the  crystal,  measurements  were  for  the  most  part  made 
by  contact  rather  than  by  reflection. 

The  following  is  a  list  of  forms  and  angles  found,  the  new  form 
being  marked  by  an  asterisk: 


e   (oil2)  +  AR 

t 

(2i34)+}R3 

E(4i36)  +  *  R$ 

/    (o22i)4 

2R 

V 

(ai3i)  +  R3 

*, 

>:(n.  4 

.13.  3)  +  i 

1    ■■*■      7 

M  (4o3i)  +  4R 

Observed 

Calculated 

Cleavage 

A   e' 

= 

(10T1) 

A 

'I012) 

=  • 

7i° 

70°   51' 

e 

A    / 

= 

(01T2) 

A 

(022l) 

= 

37°  30' 

36°   52' 

e 

A    M 

= 

(01I2) 

A 

'04?  I ) 

=  , 

77°  30' 

77°  58' 

e 

A    t 

= 

.    (01T2) 

A 

(2134) 

•  = 

21° 

200  58' 

e 

A    V 

= 

(01T2) 

A 

(2l3l) 

= 

67° 

66°  24' 

E 

A    £v 

= 

(41S6) 

A 

(5156) 

= 

i5° 

i3°     4' 

E 

A    M 

= 

(4 1 36) 

A 

'4o3i) 

= 

38°  30' 

39°  44' 

e' 

A    E 

= 

(T012) 

A     < 

[4i56> 

= 

1180 

1170     6' 

M 

A     V. 

= 

(40? 1 ) 

A     ( 

11.  4.  13. 

3) 

= 

15° 

14°  35' 

e 

A     V. 

= 

(01I2) 

A     ( 

11.  4.  13. 

3) 

= 

77° 

77°  21' 

t 

A   v: 

= 

(2l34) 

A     ( 

11.  4.  13. 

3) 

= 

72°  3°' 

72°  52' 

v. 

AV.V= 

(II 

.  4.  B.  3) 

A     ( 

15.  4.  n. 

3) 

= 

3o° 

29°     5' 

A  number  of  groups  of  calcite  crystals  from  the  Joplin  District, 
exhibited  by  a  private  collector,  Mr.  John  C.  Moore,  at  the  Louisiana 

Purchase  Exposi- 
tion, were  of  espe- 
cial interest  on 
account  of  the  large 
size  of  the  crystals 
and  the  perfection 
of  their  planes.  A 
number  of  these 
were  obtained  by 
the  Museum  (Mus. 
Nos.M  7874-7884). 
Examination  of 
the  crystals  with 
the  contact  goni- 
ometer shows  them 
to  be  made  up  of 
common  forms, 
such  as  are  already 
Fig.  3.  Calcite.  known    to   charac- 


144  Field  Columbian  Museum — Geology,  Vol.  III. 

terize  the  Joplin  calcites,  as  described  by  one  of  the  authors.* 
The  average  development  of  the  forms  is  shown  in  the  accom- 
panying figure,  Fig.  2.  The  planes  of  the  different  forms  show 
readily  recognizable  peculiarities.  Thus  the  planes  of  v  (2131) 
usually  have  brilliant,  more  or  less  undulating  surfaces,  those  of  r 
(10I1)  are  roughened  like  ground  glass,  and  those  of  w  (31I5)  are 
smooth.  The  substance  of  the  crystals  is  semi-transparent  and 
amethystine  in  color.  Needles  and  flakes  of  marcasite  are  included 
in  large  numbers  through  the  substance.  Fragments  of  the  calcite 
phosphoresce  with  a  warm  yellow  light  when  moderately  heated, 
although  Headdenf  found  only  the  yellow  Joplin  calcite  phosphor- 
escent. The  largest  crystals  measure  a  foot  in  length  and  weigh 
20-30  lbs. 

CALCITE 
BELLEVUE,  OHIO 

FIG.  1,  PLATE  XLIX 

A  crystal  of  calcite  (Mus.  No.  M  10372)  kindly  presented  to  the 
Museum  by  Mr.  S.  A.  Kurtz,  Principal  of  the  Bellevue  High  School, 
shows  some  unusual  features.  The  crystal  is  of  the  "  dog-tooth  "  form 
and  would  appear  on  casual  glance  to  be  a  polar  half  of  a  scalenohed- 
ron.  It  is  2.5  cm.  in  length  and  composed  of  colorless,  transparent 
calcite.  Mr.  Kurtz  states  that  such  crystals  occur  at  a  depth  of  about 
twenty  feet  from  the  surface  in  a  hard,  blue  layer  of  the  Niagara  lime- 
stone at  Bellevue.  An  examination  of  the  crystal  with  the  reflecting 
goniometer  shows  that  its  fundamental  forms  are  not  scalenohedrons 
but  pyramids  of  the  second  order.  .  The  dominant  one  of  these  is  y 
(8. 8.16. 3).  This,  it  is  of  interest  to  note,  was  found  by  Penfield  and 
Ford  to  be  a  dominant  form  on  silicious  calcite  from  the  Bad 
Lands,  Nebraska, J  and  Union  Springs,  New  York.§  Rogers  also 
found  it  a  dominant  form  on  calcite  from  Shullsburg,  Wisconsin.  || 
The  next  pyramid  of  the  Bellevue  specimen  cuts  the  vertical  axis  at 
one  half  the  height  of  y,  its  symbol  being  «  (4483).  Above  this  occurs 
the  pyramid  it  (1123)  cutting  the  vertical  axis  at  one  fourth  the  height 
of  «.     The  pyramids  are  thus  in  Dana's  symbols,  V"2>  I"2  anc^  f~2- 

*  Farrington,  Pub.  Field  Col.  Mus.,  1900,  Geol.  Ser.  Vol.  I,  pp.  232-241. 

t  Am.  Jour.  Sci.,  1906,  4,  21,  p.  301. 

%  Am.  Jour.  Sci.,  1900,  4,  9,  p.  353. 

§  Am.  Jour.  Sci.,  1900,  4,  10,  p.  237.  The  Union  Springs  occurrence  was  further  studied  by 
Whitlock  (Bull.  98,  New  York  State  Museum)  and  the  conclusion  reached  that  the  pyramidal 
habit  was  produced  by  crystallization  from  a  highly  siliceous  solution. 

11  Am.  Jour.  Sci.,  190*.  4,  12.  P-  42. 


Dec,  1908. 


MlNERALOGICAL   NOTES 


145 


Combined  with  the  pyramids  are  two  scalenohedrons,  one  of  which 
has  the  symbol  20.  11.  31.  11  (  +  ,»,  R  ?J)  and  the  other  occurs  be- 
tween this  form  and  a.  Although  the  latter  is  a  well-defined  plane 
no  satisfactory  reflections  could  be  obtained  from  it  for  determining 
its  symbol.  Inasmuch,  however,  as  its  zonal  relations  are  plainly 
shown  on  the  crystal,  it  is  represented  in  the  drawing,  Fig.  1,  PI.  XLIX. 
The  form  ao.xi.3x.xi  is  new  to  calcite,  and  through  the  kindly 
advice  of  Dr.  Charles  Palache,  the  letter  ft :  was  adopted  for  it.  The 
form  is  so  close  to  the  common  scalenohedron  v  (2i3i)  that  it  would 
seem  probable  that  the  latter  symbol  was  the  correct  one,  but  the 
measurements  obtained  allow  no'  other  conclusion  than  the  symbol 
above  chosen. 

The  following  are  some  of  the  measurements  obtained: 

Observed    Calculated 
«   A    «'        =       (4483)  A     (38I3) 

a   A   «v       =       (44S3)  A     (8333) 

r  a  r'  =  (8.  8. 16.  3)  a  (8.  16.  8.  3) 
r  a  rv  =  (8.  8.  T6.  3)  a  (16.  8.  8.  3) 
X  A  r       -      (8.  8. 16.  3)      a    (01TT) 

a   A   *         =       (4483)  A     (1123) 

*W   *"'    -       (n23)  A    (IT23) 

«  A  r       =      (4483)  A    (ioli) 

avA   r        -       (84?3)  A     (10T1) 

!>■: /\  !>:'   (20.  11.  31.  11)  a    (2D.  31.  IT.  11) 

ft:  a  ,"-:v  (20.  11.  3T.  11)  a    (31.  IT.  20.  11) 


54°  27' 

54°  30' 

54°  4o' 

54°  30' 

58°  28' 

58°  28' 

58°  24' 

58°  28' 

63°  40' 

63°  24' 

36°  31' 

36°  38' 

59°  7' 

59°  20' 

32°  41' 

32°  32' 

32°  24' 

32°  32' 

72°  44' 

72°  9' 

37°  27' 

37°  47' 

EPSOMITE 
WILCOX  STATION,  WYOMING 

Crystals  of  epsomite  from  the  above  locality  were  described  by 
one  of  the  authors  in  a  previous  publication.*  It  may  be  here  noted 
that  the  figure  there  given  should  be  turned  at  right  angles  to  its 
position  in  the  text  in  order  to  be  correctly  placed.  Some  time 
afterwards  the  late  Prof.  W.  C.  Knight,  to  whom  the  acquisition  of 
the  first  crystals  was  due,  kindly  furnished  about  a  dozen  additional 
individuals  which  were  somewhat  more  modified  than  those  first 
described. 

The  habit  of  these  crystals  is  stout,  prismatic.  The  largest  crystal 
was  31  mm.  (1  ^  in.)  long  in  the  direction  of  the  vertical  axis  and 

*  Pub.  Field  Col.  Mus.,  Geol.  Ser.,  Vol.  I,  p.  228. 


146 


Field  Columbian  Museum  —  Geology,  Vol.  III. 


A 

m 

= 

(010) 

A 

A 

m'" 

— 

(no) 

A 

A 

z' 

= 

(III) 

A 

A 

z"' 

= 

(III) 

A 

Calculated 

46° 

i7' 

89° 

26' 

53° 

12' 

52° 

38' 

23  mm.  (J4  in.)  long  in  the  direction  of  the  macro-axis.  All  the 
crystals  are  bounded  by  the  planes  m  (no),  b  (010),  z  (in),  and 
z'  (in),  although  occasionally  one  of  the  sphenoids  is  absent.  Some 
of  the  measurements  taken  with  the  reflecting  goniometer  on  which 
these  determinations  were  based  are  as  follows: 

Observed 
(no)  -  45°  35' 

,    (ilo)  =  8o°  20' 

(In)  =  530   12' 

(1T1)  =  520  38' 

Recognition  of  the  clinopinacoid  b  (010)  is  made  easy  by  the  prom- 
inent cleavage  in  that  direction.  In  the  development  of  the  crystals 
the  prism  m  (no),  and  one  of  the  sphenoids  z 
(in)  are  most  prominent,  although  the  clino- 
pinacoid has  in  some  of  the  crystals  a  width 
half  as  great  as  the  prismatic  faces.  Occasion- 
ally, too,  both  of  the  sphenoids  are  found  to  be 
equally  developed.  An  average  development 
of  the  faces  is  shown  in  the  accompanying 
figure  (Fig.  3.) 

The  crystals  are  simple  individuals  with 
the  exception  of  two,  each  of  which  contains 
another  individual  implanted  upon  it,  but 
not  in  any  definite  crystallographic  direction. 
The  crystals  are  all  doubly  terminated,  but  the 
Fig.  3.   Epsomite.  planes  are  frequently  imperfect  and  cavities 

are  numerous.  When  first  received  the  crys- 
tals were  colorless  and  transparent,  but  in  the  Museum  laboratory 
they  have  deliquesced. 


LEADHILL1TE 
SHULTZ,  ARIZONA 

FIG.    1,   PLATE   L 

A  specimen  of  leadhillite  from  Shultz,  Arizona,  obtained  from 
Maynard  Bixby  (Mus.  No.  M  9604),  in  the  form  of  a  single, 
large,  cuboidal  crystal  with  fragments  of  other  leadhillite  crystals 
attached,  seems  sufficiently  unlike  other  occurrences  of  the  mineral 
to  warrant  description.  The  sides  of  the  apparent  cube  of  this  speci- 
men have  a  length  of  2%  centimeters.     One  of  its  surfaces  is  yellow- 


Dec,  1908.  Mineralogical  Notes  147 

ish-green,  translucent  and  of  resinous  luster,  but  the  remaining  sur- 
faces are  coated  with  a  white,  opaque  mineral  evidently  derived  from 
alteration  of  the  underlying  substance.  This  coating  is  about  1  milli- 
meter in  thickness.  The  blowpipe  characters  of  the  principal  mineral 
agree  with  those  of  leadhillite,  and  those  of  the  coating  mineral  with 
cerussite.  Alteration  of  leadhillite  to  cerussite  was  also  observed  by 
Penfield  on  crystals  from  this  locality.*  While  the  large  crystal  under 
consideration  had  an  apparently  cubical  form,  measurements  of  the 
angles  with  the  reflecting  goniometer,  secured  by  attaching  cover 
glasses  to  the  planes,  gave  870  5',  870  30'  and  870  48'.  These  results  sug- 
gested the  presence  of  a  rhombohedron,  especially  as  an  apparently 
rhombohedral  form  of  leadhillite,  known  as  susannite,  has  been 
observed.  Moreover,  a  well-marked  cleavage  truncating  the  solid 
angle  in  a  manner  corresponding  to  the  basal  cleavage  of  the  rhom- 
bohedron occurs  on  the  crystal.  The  angles  of  this  cleavage  upon 
the  planes  of  the  crystal  are  as  follows:  510  20',  51°  57',  520  45'. 
These  angles  closely  resemble  those  given  for  the  rhombohedron  of 
susannite  by  Dana,f  his  value  for  c  a  r  being  1280  3'  and  for  r  a  r', 
940.  It  is  thus  apparent  that  the  interfacial  angles  of  the  crystal 
would  admit  of  its  interpretation  as  a  rhombohedron.  On  examin- 
ing the  cleavage  plates  with  the  polarizing  microscope,  however,  well- 
marked  biaxial  characters  appear.  Interference  figures  perpendicular 
to  the  acute  bisectrix  are  exhibited,  with  dispersion  p  <  v  and  a  nega- 
tive optical  character.  It  is  thus  obvious  that  the  crystal  should  be 
interpreted  as  monoclinic  and  must  therefore  probably  be  regarded 
as  made  up  of  a  negative  pyramid  and  an  orthodome.  The  pyramid 
and  dome  most  nearly  corresponding  with  the  angles  given  above  are 
t  (112)  and  /  (Toi),  the  measured  and  calculated  angles  for  these 
forms  comparing  as  follows: 

(I01) 

(112) 
(Il2) 

Fig.  1,  PI.  L,  shows  the  form  thus  produced.  The  habit  seems 
not  to  have  been  hitherto  observed  in  leadhillite  except  in  so  far  as  it 
may  resemble  the  rhombohedral  habit  of  susannite.  The  specific 
gravity  of  the  mineral  was  found  to  be  6.42. 

*  Dana,  System  of  Mineralogy,  1892,  p.  922. 
+  Syst.  Min.,  1854,  p.  373. 


c  (cleavage)    a   / 

= 

(001)     A 

c                        A    t 

= 

(001)     A 

t    A    f 

= 

(112)     A 

Observed 

Calculated 

5i°  57' 

5i°  5i' 

52°  45' 

5i°  5J' 

87°     5' 

85°     6' 

148  Field  Columbian  Museum  —  Geology,  Vol.  III. 

LINARITE 
EUREKA,   UTAH 

FIGS.   2  AND  3.    PLATE   L 

Several  specimens  of  linarite  from  Eureka,  Utah,  were  obtained 
from  Maynard  Bixby.  Of  these  one  specimen,  Mus.  No.  M  9616, 
was  especially  remarkable  for  its  size  and  perfection.  The  linarite  oc- 
curs in  this  specimen  as  a  single  crystal  attached  to  a  siliceous  matrix. 
On  casual  inspection  the  crystal  has  the  appearance  of  a  nearly  square 
prism  terminated  by  two  dome  planes.  Measurement,  however, 
shows  that  the  crystal  is,  as  is  usual  with  linarite,  elongated  in  the 
direction  of  the  ortho-axis,  the  two  apparent  domes  being  the  unit 
prism.  The  length  of  the  crystal  in  the  direction  of  the  ortho-axis 
is  12  millimeters,  and  its  width  6  millimeters.  A  re-entrant  angle  sug- 
gested that  the  crystal  was  probably  twinned  upon  the  basal  plane, 
but  as  it  was  deemed  undesirable  to  remove  the  crystal  from  its 
matrix,  no  careful  study  of  this  feature  could  be  made.  The  color  of 
the  crystal  is  the  deep  azure-blue  characteristic  of  linarite,  and  is  so 
deep  as  to  make  the  crystal  as  a  whole  practically  opaque.  On  an- 
other specimen,  Mus.  No.  M  9617,  several  smaller  crystals  occurred 
which  permitted  removal  for  measurement  with  the  reflecting  goni- 
ometer. The  habit  and  attachment  of  some  of  these  were  the  same 
as  those  of  the  large  crystal,  while  others  showed  a  more  nearly  tabu- 
lar habit.  The  crystal  selected  for  goniometric  measurement  ex- 
hibted  the  same  habit  as  the  large  crystal  and  was  6  millimeters  long 
by  3  millimeters  wide.  Its  orientation  was  determined  by  well- 
marked  cleavage  parallel  to  the  orthopinacoid.  On  this  crystal  in 
the  zone  of  orthodomes  two  forms  new  to  linarite  were  determined. 
These  were  8  (10.0.9)  and  0  (S.o.io).  Of  these  <£,(9.o.io)  was  the  better 
developed.  The  occurrence  of  the  domes  and  base  nearly  at  right 
angles  to  a  (100)  gives  the  crystal  a  characteristically  hexagonal 
appearance  when  viewed  in  the  direction  of  the  ortho-axis.  In 
the  pyramidal  zone  a  new  form  f  (323)  was  observed.  Its  deter- 
mination was  based  on  its  occurrence  in  the  zone  mgr  and  the  angle 
f  a  m'  =  (323)  A  (Tio)  =  52°  45'.  It  will  be  noted  that  this  pyramid 
occurs  in  the  same  zone  with  the  unit  dome  5  (Toi),  and  if  this  dome 
had  been  present  in  the  crystal,  as  is  frequently  the  case  with  linarite, 
a  measurement  would  have  been  obtained  of  it  in  that  zone.  As  a 
matter  of  fact,  however,  the  dome  which  actually  occurs  was  outside 
the  zone  mgr.     This  affords  additional  proof  of  the  correctness  of  its 


Dec,  1908. 


MlNERALOGICAL   NOTES 


149 


determination  as  <f>  (S.0.10),  although  its  position,  so  near  that  of  the 
unit  dome  common  to  linarite,  would  suggest  the  possibility  of  its 
being  confused  with  the  latter.  It  may  also  be  noted  that  the  meas- 
urement from  a  (100)  a  c  (001),  is  nearly  the  same  as  from  a  (100) 
a  <f>  (9.o.io).  This  would  suggest  twinning  on  the  orthopinacoid, 
but  on  careful  study  of  the  crystal  no  evidence  of  twinning  could  be 
observed.  The  interpretation  given  above  seems,  therefore,  to  be 
the  most  reasonable  one.  The  pyramid  /  (£23)  exhibits  somewhat 
rounded  faces;  the  dome  u  (2oi)  is  also  characterized  by  somewhat 
undulating  surfaces.  No  special  characters  were  noted  regarding 
the  other  planes.  The  appearance  of  the  crystal  as  a  whole  is  shown 
in  Fig.  2,  PI.  L.  In  Fig.  3,  PI.  L  a  projection  of  these  forms 
upon  the  clinopinacoid  is  shown.  This  exhibits  to  good  advantage 
the  characteristic  zones  of  the  crystal  and  its  nearly  square  appearance 
when  seen  in  the  direction  of  the  ortho-axis.  The  following  is  a  list 
of  the  forms  observed,  together  with  some  of  the  measured  and  cal- 
culated angles.     The  new  forms  are  marked  with  an  asterisk. 


c  (001) 

*0  (9.  0. 

10) 

a  ( 

100) 

x  (302) 

m  (no) 

u   (2oi) 

r  (on) 

•  g  (Z11) 

*S  (10.  0.  9) 

*/    $23] 

Observed            Calculated 

c 

A 

X 

= 

(001)    A 

(3o2) 

= 

39° 

59' 

40°  3X' 

c 

A 

u 

= 

(001)    A 

(2oi) 

= 

5o° 

14' 

50°  6' 

c 

A 

a 

= 

(001)    A 

(100) 

= 

77° 

27' 

77°  22'  40 

c 

A 

8 

= 

(001)    A 

(10.  0. 

9) 

= 

24° 

32' 

25°  8' 

c 

A 

4> 

= 

(001)    A 

(5.  0.  10) 

= 

25° 

15' 

25°  23' 

r 

A 

m 

= 

(on)    A 

(no) 

= 

5o° 

48' 

5i°  9' 

r 

A 

a 

= 

(oil)    A 

(100) 

= 

8o° 

28' 

8o°  13' 

g 

A 

m' 

= 

(2li)     A 

(Iio) 

= 

42° 

50' 

42°  53' 

I 

A 

a' 

mm 

(2ll)     A 

(Too) 

- 

59° 

1 1' 

59°  27' 

f 

A 

m' 

= 

(523)      A 

(lio) 

= 

52° 

45' 

52°  40' 

150  Field  Columbian  Museum  —  Geology,  Vol.  III. 


M1METITE 
EUREKA,   UTAH 

FIGS.  4  AND  5.  PLATE  L 

On  several  specimens  from  Eureka,  Utah,  obtained  from  Maynard 
Bixby,  mimetite  occurs  in  acicular  form.  In  one  of  these  specimens 
(Mus.  No.  M  8384),  the  crystals  are  in  the  form  of  minute  white 
needles  occurring  in  great  abundance  coating  pyramidal  crystals  of 
anglesite.  On  another  specimen  (Mus.  No.  M  8385),  the  crystals 
are  larger,  reaching  a  length  of  1  cm.  with  a  thickness  of  .75  mm. 
These  crystals  are  transparent  and  colorless.  Many  of  them  show  a 
termination  in  which  it  is  possible  to  recognize  definite  crystal  planes, 
and  examination  with  the  reflecting  goniometer  permits  identifica- 
tion of  the  unit  prism  m  (10T0),  the  unit  pyramid  x  (10T1)  and  the 
basal  plane  c  (0001).  Fig.  4,  PI.  L,  shows  the  characteristic  devel- 
opment. In  another  specimen  (Mus.  No,  M  9383),  the  mimetite 
exhibits  the  same  habit,  but  the  crystals  are  somewhat  shorter  and 
have  a  wine-yellow  color.  These  crystals  have  an  average  diameter 
of  .6  mm.  and  reach  a  length  of  5  mm.  The  forms  of  which  they 
are  composed  are  similar  to  those  previously  mentioned,  but  the 
basal  plane  is  more  extensively  developed  as  shown  in  Fig.  5,  PI.  L. 
No  doubly  terminated  crystals  were  found.  Neither  the  colorless 
nor  the  yellow  crystals  exhibit  noticeable  absorption  or  pleochro- 
ism  in  polarized  light  in  the  direction  of  the  vertical  axis.  On 
heating,  the  yellow  crystals  change  to  a  smoky  color. 


OCTAHEDRITE 
JEQUIT1NHONHA   RIVER,  BRAZIL 

FIGS.  2-4,  PLATE  LI 

Several  crystals  of  octahedrite  were  presented  to  one  of  the  authors 
by  Olaf  E.  Ray,  Esq.,  an  official  of  the  Chicago  Brazilian  Diamond 
Company.  These  crystals  were  obtained  from  washings  of  the  dia- 
mond-bearing sand  of  the  Jequitinhonha  River,  near  Diamantina, 
Brazil.  The  crystals  have  the  typical  pyramidal  character  of  octahe- 
drite and  range  from  5  to  8  mm.  in  length.  Their  color  is  the 
typical  brownish-black  of  the  mineral  showing  greenish-yellow  by 
transmitted  light.  Aside  from  striations  the  planes  are  splendent. 
The  edges  are  somewhat  rounded  from  stream  rolling,  but  otherwise 
the  crystals  are  well  developed  and  give  excellent  signals  with  the 


Dec,  1908.  Mineralogical  Notes  151 

reflecting  goniometer.  Probably  the  most  remarkable  feature  ex- 
hibited by  the  crystals  is  their  apparently  hemimorphic  develop- 
ment. This  development  is  shown  in  Figs.  3  and  4,  PI.  LI.  Thus 
the  crystal  shown  in  Fig.  3,  PI.  LI,  exhibits  at  one  end  a  small  basal 
plane  with  several  modifying  pyramids,  while  at  the  opposite  end 
the  basal  plane  alone  occurs.  Again,  the  crystal  shown  in  Fig.  4, 
PI.  LI,  shows  one  end  considerably  modified  by  pyramids,  while  the 
other  possesses  no  modifying  planes  whatever.  Such  crystals  might 
be  expected  to  show  pyro-electricity  but  careful  tests  for  this  property 
made  with  the  kindly  assistance  of  Prof.  R.  A.  Millikan,  of  the  Uni- 
versity of  Chicago,  gave  no  indications  of  its  presence.  The  apparent 
hemimorphism  is  perhaps  therefore  to  be  regarded  as  due  to  distortion 
only.  Other  interesting  illustrations  of  distortion  or  merohedrism 
are  shown  by  the  crystals.  Thus  on  the  crystal  shown  in  Fig.  3,  PI. 
LI,  but  a  single  plane  of  the  pyramid  v  (117)  occurs,  while  the  other 
forms  are  present  in  normal  number.  The  crystal  shown  in  Fig.  4, 
PI.  LI,  exhibits  two  planes  of  the  pyramid  v  (117)  and  two  planes  of 
the  pyramid  r  (115).  In  addition  occur  two  planes  only  of  the  dite- 
tragonal  pyramid  st  (5.1. 19).  On  the  crystal  shown  in  Fig.  2,  PI.  LI, 
a  single  plane  of  the  pyramid  of  the  second  order  G  (104)  occurs  and 
a  pyramid  new  to  octahedrite,  M  (338)  is  present  as  two  planes,  while 
the  development  of  the  other  pyramids  is  normal  in  character.  No 
differentiation  of  the  planes  in  luster  or  etching  figures  can  be  noted 
except  that  the  pyramid  of  the  second  order  G  (104)  shows  numerous 
pittings.  In  addition  the  dominant  pyramid  p  (in)  is  always  charac- 
terized by  striations  parallel  to  the  base.  The  total  forms  observed 
with  angles  follow,  the  one  marked  with  an  asterisk  being  new.  The 
letter  G  has  been  given  to  the  form  104,  this  form  having  been  listed 
by  Hintze*  but  not  lettered: 

sx   (5-  i-  19) 


c     (00 1 ) 

r     (115) 

G  (104) 

v     (117) 

P     (ill) 

*M  (338) 

p 

A    p" 

-        (HI) 

A 

(III) 

r 

a  r* 

-    (us) 

A 

(n5) 

V 

A    V" 

-   (117) 

A 

(117) 

c 

A    G 

=    (001) 

A 

(104) 

c 

A    M 

-     (001) 

A 

(338) 

st 

A    *,' 

-      (5-  i-  19) 

A 

(1.  5-  19) 

P 

A    5, 

-      (in) 

A 

(5-  i-  19) 

r 

A    5, 

-      (115) 

A 

(5-  i-  19) 

v"  a    st 

-      (1T7) 

A 

(s-  i-  19) 

*  Handbuch  der  Mineralogie, 

xqo6 

,  Bd.  I,  p.  1563 

Observed 

Calculated 

I36°   32' 

136°  36' 

53°  i4' 

53°  22' 

39°  44' 

39°  3°' 

23°  48' 

23°  58' 

43°  5i' 

43°  i87 

27°  33' 

27°  38' 

48°     5' 

48°    12' 

14°  46' 

14°  4i' 

21°   28' 

21°    32' 

152  Field  Columbian  Museum— Geology,  Vol.  III. 


OLIVENITE 
TINTIC   DISTRICT,  UTAH 

PLATE  LII 

Crystals  of  olivenite  from  this  locality  have  been  previously  de- 
scribed by  Washington,*  but  a  large  suite  of  specimens  received  from 
Maynard  Bixby  affords  some  new  characters  which  seem  worthy 
of  description.  The  olivenite  in  these  specimens  occurs  both  as  well- 
defined  crystals  and  in  the  fibrous  form  known  as  wood-copper.  For 
the  most  part  the  crystals  present  the  dark  olive-green  color  char- 
acteristic of  olivenite,  although  there  are  some  variations  from  this, 
as  will  be  noted.  None  of  the  crystals  is  highly  modified,  nor  are  they 
of  large  size.  For  the  most  part  they  exhibit  a  prismatic  habit  and 
occur  encrusting  cavities  in  a  cupriferous  gangue.  The  largest  crystals 
noted  (Mus.  No.  M  9414)  are  represented  by  Fig.  1,  PI.  LII.  These 
crystals  are  scattered  in  radiated  fashion  over  a  siliceous  matrix  and 
reach  in  some  cases  a  length  of  1  cm.  They  are  usually  attached 
by  the  macropinacoid  a  (100).  As  shown  in  the  figure,  they  are 
simple  in  form,  being  made  up  of  the  unit  prism  m  (no),  the 
macropinacoid  a  (100)  and  the  brachydome  d  (025).  This  dome  is  a 
form  new  to  olivenite.  Its  determination  was  based  on  a  good  meas- 
urement oi  d  a  d'  =  320  45'.  A  somewhat  similar  habit  is  ex- 
hibited by  the  crystals  shown  in  Fig.  2,  PI.  LII  (Mus.  No.  M  9400), 
except  that  the  basal  plane  occurs  here  and  the  macropinacoid 
is  lacking.  The  dome  and  base  are  characterized  by  striations 
||  to  a  (100).  These  crystals  are  of  dark,  nearly  black,  color,  about 
1  mm.  in  length  and  occur  thickly  encrusting  a  somewhat  porous 
gangue.  Another  simple  habit  consists  only  of  the  unit  prism  and 
basal  plane,  producing  a  tabular  form.  This  is  exhibited  in  Fig.  3, 
PI.  LII  (Mus.  No.  M  9413).  These  crystals  occur  lining  a  cavity  about 
one  inch  in  diameter.  Sheaf-like  crystals  of  azurite  of  a  tabular  habit 
are  implanted  upon  the  olivenite.  The  olivenite  crystals  are  of  a  light 
olive-green  color,  with  dull  planes,  and  are  usually  attached  by  the 
basal  plane.  The  average  length  of  these  crystals,  measured  in 
the  direction  of  the  macro-axis  is  5  mm.  A  rather  unusual  habit  for 
olivenite  is  that  represented  in  Fig.  4,  PI.  LII  (Mus.  No.  M  9421). 
These  crystals  are  elongated  in  the  direction  of  the  brachy-axis. 
The  extension  seems  to  be  rather  the  result  of  growth  of  a  number  of 

♦Am.  Jour.  Sci.,  1888,  3,  35,  p.  298. 


Dec,  1908.  Mineralogical  Notes  153 

crystals  in  a  parallel  direction  than  the  development  of  a  single  crystal. 
Nevertheless  many  of  the  planes  give  reflections  like  those  of  a  single 
plane.  The  color  of  these  crystals  is  a  dark  olive-green  and  they 
usually  exhibit  a  radiated  arrangement  in  their  attachment.  The 
individual  crystals  are  attached  by  the  end  of  the  brachy-axis,  their 
length  averaging  about  5  mm.  The  planes  are  as  a  whole  bril- 
liant and  give  fair  reflections.  Fig.  5,  PI.  LII,  represents  a  habit 
tabular  with  respect  to  a  (100) .  This  habit  is  exhibited  by  the  crystals 
of  a  single  specimen,  Mus.  No.  M  9403.  These  crystals  are  very  small, 
their  greatest  length  being  .5  mm.  and  thickness  .1  mm.  They  are 
also  peculiar  in  being  nearly  transparent  and  having  a  pale  olive- 
green  color  rather  than  the  deep  green  to  black  usually  characteristic 
of  the  mineral.  The  cavity  in  which  the  crystals  occur  is  lined 
with  chrysocolla,  and  upon  this  the  olivenite  is  implanted.  The 
above  specimens  are  all  from  Eureka,  Utah.  A  single  specimen,  Mus. 
No.  M  9419,  from  Mammoth,  Utah,  exhibits  crystals  differing  some- 
what in  habit  from  any  of  the  above.  This  habit  is  shown  in  Fig.  6, 
PI.  LI,  and  is  characterized  by  prominent  development  of  the  basal 
planes,  and  elongation  in  the  direction  of  the  macro-axis,  producing  a 
tabular  form.  A  brachydome  not  previously  noted  on  olivenite  also 
occurs  on  these  crystals.  This  lies  between  the  base  c  (001)  and  the 
unit  dome  e  (on)  and  its  determination  is  based  upon  its  occurrence 
in  the  zone  noted  and  the  measurement  e  /\  s  =  70  50'.  Occur- 
ring with  crystals  of  this  habit  are  others  of  the  habit  shown  in  Fig. 
2,  PI.  LII.  All  the  crystals  on  this  specimen,  Mus.  No.  M  9419,  are 
greenish-black  in  color,  opaque,  and  have  brilliant  planes.  They 
occur  encrusting  cavities  in  massive  malachite. 

In  the  measurement  of  the  crystals  as  a  whole  it  was  found  that 
the  angles  observed  did  not  agree  with  those  obtained  from  the  axial 
ratios  of  Washington  as  fully  as  could  be  desired.  This  discrepancy 
was  especially  noticeable  in  the  measurement  of  the  prism  m  a  m"' . 
A  large  number  of  measurements  of  this  angle  gave  a  value  closely 
approximating  870  28',  which  differs  nearly  a  degree  from  that 
obtained  by  Washington,  his  value  being  86°  26'.  Further,  the 
measurement  obtained  for  e  a  e' ,  approximated  in  several  good 
measurements  closely  to  the  value  690  18'.  These  values  agree  more 
closely  with  the  measurements  of  Phillips  *  than  with  those  of  Washing- 
ton. The  excellence  of  the  measurements  on  the  Eureka  crystals 
seemed  to  warrant  the  calculation  of  axial  ratios  from  them,  and  these 

♦Mineralogy,  1823,  p.  319 


154  Field  Columbian  Museum  —  Geology,  Vol.  III. 

were  accordingly  obtained  as  follows,  the  ratios  of  Washington  and 
Phillips  being  given  for  comparison: 

a  :  b  :  c  =  0.95873  :  1  ;  0.691 14,  Farrington  and  Tillotson. 

a  :  b  :  c  =  0.9573    :  1  :  0.6894,  Phillips. 

a  :  b  :  c  =  0.9396    :  1  :  0.6726,  Washington. 

The  total  forms  observed  with  the  measured  and  calculated  angles 
are  as  follows,  new  forms  and  fundamental  measurements  being 
marked  with  an  asterisk: 


a    (100) 

V 

(101) 

b     (010)    . 

e 

(on) 

c     (001) 

%  <f 

(034) 

m    (no) 

*d 

(025) 

Observed 

Calculated 

m 

A 

m!" 

= 

(no)    a    (1T0) 

= 

*87°   28' 

e 

A 

e' 

= 

(on)    a    (0T1) 

= 

*69°    l8' 

a 

A 

V 

= 

(100)    a    (101) 

= 

53°  59' 

54°     9' 

e 

A 

s 

= 

(on)    a    (034) 

= 

7°  5o' 

7°   15' 

d 

A 

d' 

= 

(025)    a    (025) 

= 

32°  45' 

32°    20' 

No  marked  pleochroism  of  any  of  the  crystals  could  be  observed. 
On  examination  of  some  of  the  acicular  forms  with  the  polarizing 
microscope  the  usual  characters  were  observed  with  the  exception  that 
a  red  variety  occurred  which  does  not  seem  to  have  been  hitherto  men- 
tioned. These  crystals  are  characterized  by  a  brownish-red  color, 
occur  in  tufts,  and  the  individuals  average  from  .5  to  2  mm.  in  length. 
They  are  transparent  and  of  marked  brownish-red  color  but  show 
little  or  no  pleochroism. 


ORP1MENT 
MERCUR,  UTAH 

PLATES  XLIV  AND  LIII 

Among  the  specimens  obtained  from  Maynard  Bixby,  orpiment 
from  Mercur,  Utah,  was  represented  by  an  especially  notable  one, 
(Mus.  No.  M  8206).  This  specimen  consisted  of  a  piece  of  limestone 
about  3x4  inches  in  size,  upon  which  were  implanted  about  fifteen 
large  crystals  of  orpiment  together  with  fragments  of  orpiment 
crystals  and  numerous  crystals  of  calcite.  The  size  and  perfection 
of   many  of  the  orpiment  crystals  seem  to  exceed  any  that  have 


Dec,  1908.  Mineralogical  Notes  155 

been  hitherto  described.  The  largest  of  the  crystals  measure  20 
millimeters  in  length  by  17  millimeters  in  width,  and  from  this 
they  diminish  to  about  one-half  this  size.  They  are  arranged 
upon  the  matrix  in  a  nearly  parallel  position  though  not  exactly 
so.  The  mode  of  attachment  may  be  in  general  stated  to  be  that 
of  the  lower  end  of  the  vertical  axis,  though  this  attachment  varies 
somewhat.  The  crystal  planes  do  not  present  brilliant  surfaces, 
but  though  dull  are  not  rounded.  They  do  not  afford  sharp  signals 
with  the  reflecting  goniometer,  but  give  tokens  sufficiently  well  de- 
fined so  that  very  close  estimates  of  the  angular  values  can  be  ob- 
tained. The  cleavage  parallel  to  the  clinopinacoid  is,  as  usual,  very 
strongly  marked.  This  cleavage  affords  reflections  which  are  sharp 
but  vicinal.  The  color  of  the  crystals  is  a  dark  orange-red,  on 
cleavage  surfaces  bright  golden-yellow.  The  crystals  are  opaque. 
In  development  the  crystals  exhibit  monoclinic  symmetry  throughout 
and  leave  little  doubt  that  orpiment  should  be  considered  as  crystal- 
lizing in  this  system.  They  are  all  of  the  same  habit  and  one  which 
seems  to  be  new  for  this  mineral.  It  is  especially  characterized  by  the 
large  development  of  the  positive  pyramid  v  (343).  This  occurs  in 
broad  planes,  sometimes  1.5  cm.  in  length  by  1  cm.  in  width. 
Grouped  with  this  pyramid  occurs  in  greater  or  less  development 
the  pyramid  w(l2i).  Accompanying  this  occur  several  prisms  and 
in  less  prominent  development  several  other  pyramids.  The 
habit  generally  exhibited  is  illustrated  in  Fig.  1,  PI.  LI II,  the  crystal 
being  drawn  in  the  normal  position.  As  this  position  is  not,  however, 
favorable  to  exhibiting  the  positive  pyramid,  Fig.  2,  PI.  LIII,  shows 
the  crystal  drawn  in  reverse  position.  Three  forms  new  to  orpiment 
were  detected  upon  the  crystals.  These  were  the  3/2  clinodome,  023, 
designated  as  /,  the  1/3  negative  pyramid  I33  designated  as  n,  and 
the  1/3  positive  orthodome  I03  designated  as  d.  In  addition  two 
forms  were  noted  which  had  been  observed  by  Stevanovic,*  but  to 
which  he  had  assigned  no  letters,  apparently  because  he  did  not 
regard  his  results  as  conclusive.  These  forms  were  the  1/3  negative 
orthodome  103  to  which  the  letter  e  has  been  assigned,  and  the  posi- 
tive pyramid  T23  to  which  the  letter  k  has  been  assigned.  The 
habit  of  the  Mercur  crystals,  it  may  be  noted,  somewhat  resembles 
that  of  one  figured  by  Stevanovic  f  from  Allchar  except  that  in  the 
crystal  figured  by  him,  the  prisms  are  the  prominent  forms  instead 
of  the  pyramids.  A  basal  projection  showing  the  usual  development 
of  the  different  forms  found    upon  the  Mercur  specimen   is  given 

*Zs.  Kr..  IQ04.  39,  P-  14.  tLoc.  cit.    Fig.  3. 


156 


Field  Columbian  Museum  —  Geology,  Vol.  III. 


in  Fig.  3,  PI.  LIIL  In  calculating  the  forms  the  axial  ratios  estab- 
lished by  Stevanovic  have  been  employed  rather  than  those  of  Mohs. 
These  values  are  as  follows: 


a  :b  :  c     =     0.5962  :  1  :  0.665 


0    =    90°  41' 


The  following  is  a  list  of  the  forms  observed  on  the  Mercur  orpi- 
ment,  those  marked  with  an  asterisk  being  new: 


a    (100) 

e  (103) 

q    (449> 

b    (010) 

*d  (I03) 

k   (I23; 

I 

m    (no) 

*l  (023) 

*n  (13  3 

) 

m    (120) 

v     (343) 

*  (243; 

1 

0     (101) 

v     (I21) 

Observed 

Calculated 

b 

A 

0 

=      (010) 

A 

(101) 

= 

90° 

28' 

90°  oo' 

a 

A 

m 

=      (100) 

A 

(no) 

— 

3i° 

2' 

30°   48' 

a 

A 

u 

=      (100) 

A 

(120) 

= 

5o° 

io' 

5o°      i' 

a 

A 

0 

=      (100) 

A 

(101) 

= 

4i° 

i9' 

41°  35' 

a 

A 

e 

=      (100) 

A 

(103) 

= 

7o° 

8' 

69°    14' 

e 

A 

d 

=      (103) 

A 

(T03) 

= 

40° 

58 

41°  32' 

b 

A 

I 

=      (010) 

A 

(023) 

= 

65° 

23' 

66°     5' 

0 

A 

I 

=      (101) 

A 

(023) 

= 

54° 

35' 

53°   14' 

V 

A 

v' 

=      (343) 

A 

(343) 

= 

6i° 

34' 

6i°  32' 

V 

A 

v' 

=      (T21) 

A 

(T2i) 

= 

82° 

58' 

83°  32' 

b 

A 

n 

=      (010) 

A 

(133) 

= 

59° 

457 

58°  21' 

0 

A 

n 

=      (101) 

A 

(133) 

= 

7o° 

35 

72°    22' 

b 

A 

k 

=      (010) 

A 

(T23) 

= 

68° 

41' 

67°  44' 

0 

A 

k 

=      (101) 

A 

(T23) 

= 

7o° 

00' 

7o°  48' 

b 

A 

q 

=      (010) 

A 

(549) 

= 

75° 

52' 

75°     6' 

b 

A 

i 

=      (010) 

A 

(243) 

= 

54° 

2l' 

54°  43' 

0 

A 

i 

=      (101) 

A 

(243) 

= 

36° 

17' 

36°  50' 

In  connection  with  these  crystals  the  well-known  crystals  *  from 
this  locality  occurring  in  cavities  in  clay  were  examined.  These 
crystals  are  of  smaller  size  and  are  for  the  most  part  obviously  twins 
but  their  planes  were  found  to  be  so  poorly  developed  that  no  satis- 
factory measurements  could  be  obtained. 

*  App.  Dana's  Mineralogy,  i8qq,  p.  so. 


Dec,  1908. 


MlNERALOGICAL   NOTES 


157 


PHENACITE 
NORTH   CHATHAM,   NEW  HAMPSHIRE 

The  first  published  mention  of  phenacite  from  this  locality  seems 
to  have  been  by  Kunz  in  1890*  This  brief  mention  may  be  repeated 
here: 

"In  May,  1888,  E.  A.  Andrews,  of  Stow,  Me.,  discovered  some 
crystals  of  phenacite  on  Bald  Mountainf,  North  Chatham,  N.  H.,  near 
the  State  line  be- 
tween Maine  and 
New  Hampshire 
and  in  the  neigh- 
borhood of  Stone- 
ham,  Me.  They 
were  found  in  a 
vein  of  coarse 
albitic  granite,  as- 
sociated with  crys- 
tals  of  smoky 
quartz,  topaz  and 
muscovite,  some 
implanted      on 

smoky  quartz,  and  a  few  attached  so  loosely  to  the  matrix  by  one 
of  the  rhombohedral  faces  that  they  could  be  removed  without  being 
broken.  They  were  about  fifty  in  number,  lenticular  in  shape,  and 
measured  from  ^  inch  to  %  inch  (3  mm.  to  12  mm.)  across,  and 
from  1-25  inch  to  %  inch  (1  mm.  to  3  mm.)  in  thickness.  They 
were  all  white  or  colorless,  with  polished  faces,  and  for  the  most  part 
very  simple  in  form." 

No  crystallographic  investigation  seems  to  have  been  undertaken 
by  Kunz  and  no  further  mention  of  the  occurrence  has  been  made  so 
far  as  the  writers  are  aware.  The  Museum  is  in  possession  of  three 
specimens  of  phenacite  from  this  locality.  In  two  of  the  specimens 
single  phenacite  crystals  are  implanted  on  crystals  of  smoky  quartz. 
The  phenacite  crystals  of  these  specimens  are  about  10  mm.  in  diam- 
eter and  5  mm.  thick.  They  are  whitish  in  color  and  semitransparent. 
They  exhibit  the  lenticular  habit  mentioned  by  Kunz,  this  habit  be- 
ing   produced  by  the  prominence  of     the   rhombohedron  r  (ioli). 


Fig. 


Phenacite. 


•Gems  and  Precious  Stones  of  North  America,  1890,  p.  100. 

tThe  correct  name  of  the  mountain  is  Bald  Face  Mountain. — O.  C.  F. 


158  Field  Columbian  Museum  —  Geology,  Vol.  III. 

This  is  also  usually  truncated  by  the  positive  %  rhombohedron  d 
(01T2).  The  unit  prism  m,  ( 1 0T0)  also  appears  as  small  planes.  The 
third  specimen  (Mus.  No.  M  10276)  consists  of  a  large  crystal  of  ortho- 
clase  3x5  inches  in  size  more  or  less  intergrown  with  albite,  and  show- 
ing also  three  crystals  of  topaz  2  to  3  inches  in  length.  Scattered 
about  upon  the  albite  and  orthoclase  about  50  crystals  of  phenacite 
occur.  These  vary  in  diameter  from  1  cm.  to  1  mm.  All  are 
whitish  to  colorless,  the  larger  crystals  tending  to  be  semitrans- 
parent  and  the  small  ones  perfectly  transparent.  In  habit  all  show 
the  lenticular  shape  previously  described,  which  is  produced  by 
the  forms  already  mentioned.  Many  of  the  smaller  crystals,  how- 
ever, are  more  highly  modified  than  the  large  ones  and  the  planes 
being  brilliant  and  giving  good  reflections  afford  easy  identification 
of  the  forms.  The  following  is  a  list  of  the  forms  observed  and  some 
of  the  measurements  obtained : 


m 

(iolo)          d 

(0112) 

5      (2l3l) 

a 

(11 

2o)          p 

(1 123) 

s,   (3121) 

r 

(10 

Ti) 

Observed 

Calculated 

a 

A 

r 

= 

(li2o) 

A 

(lOll) 

= 

58°   14' 

58°    18' 

r 

A 

P 

= 

(10I1) 

A 

(n23) 

= 

20°     II' 

20°      4' 

r 

A 

m 

= 

(10I1) 

A* 

(iolo) 

= 

52°   41' 

52°   39' 

m' 

A 

d 

= 

(oilo) 

A 

(0112) 

= 

68°  35' 

69°      7' 

r 

A 

d 

= 

(loli)j 

A 

(0II2) 

= 

3i°  35' 

3i'   42' 

r 

A 

s 

= 

(lOll) 

A 

(2l3l) 

= 

3o°   17' 

29°  57' 

s 

A 

*, 

= 

(2l3l) 

A 

(1231) 

= 

55°  4o' 

56°  42' 

The  appearance  of  one  of  the  crystals  is  shown  in  the  accompany- 
ing figure,  Fig.  4,  it  having  been  drawn  as  is  usual  with  phenacite, 
with  the  negative  rhombohedrons  in  front. 


REALGAR 
MERCUR,  UTAH 

PLATES  XLIV  AND  LIV 

Among  other  specimens  from  Mercur,  Utah,  obtained  from  May- 
nard  Bixby,  two  exhibiting  realgar  deserve  especial  mention.  In 
one  of  these  specimens  (Mus.  No.  M  8204),  the  realgar  occurs  as  small 
crystals  partially  filling  a  narrow  fissure  in  limestone:  in  the  other 
(Mus.  No.  M  8205)  it  occurs  as  elongated  prisms  intergrown  with 


Dec,  1908.  Mineralogical  Notes  159 

large  and  small  calcite  crystals.  The  color  of  the  realgar  in  both 
specimens  is  a  superb  carmine-red.  The  crystals  are  transparent. 
The  habit  of  the  crystals  in  the  specimen  numbered  M  8204  is,  as  is 
usual  with  realgar,  short-prismatic.  These  crystals  are  highly  modi- 
fied and  doubly  terminated.  A  marked  feature  is  the  large  number 
of  prisms  present,  no  less  than  nine  being  observed.  The  planes  are 
remarkably  brilliant  and  afford  excellent  signals  on  the  reflecting 
goniometer.  The  prisms  are  often  scarcely  more  than  lines,  but 
nevertheless  give  well-defined  signals  with  the  goniometer.  In  some 
of  the  crystals  the  basal  plane  is  quite  prominent,  while  in  others 
pyramids  and  clinodomes  are  extensively  developed.  The  clinopina- 
coid  may  also  be  quite  fully  developed.  The  two  most  prominent 
types  exhibited  by  these  crystals  are  shown  in  Figs.  1  and  2,  PI. 
LIV.  As  there  represented,  a  slight  elongation  in  the  direction  of 
the  clino-axis  usually  occurs.  The  crystals  average  about  4  mm.  in 
length. 

The  specimen  numbered  M  8205  is  from  the  Golden  Gate  mine. 
In  habit  the  crystals  of  this  specimen  seem  to  be  different  from  any 
hitherto  noted  in  realgar  in  that  the  prism  is  elongated  in  the  direction 
of  the  vertical  axis.  None  of  these  crystals  is  doubly  terminated. 
The  terminations  on  the  single  terminated  end  are  simple  as  com- 
pared with  those  of  the  crystals  previously  described  and  there  is  no 
large  number  of  prisms  present.  The  prismatic  development  here  is 
produced  chiefly  by  the  prisms  m  (no)  and  /  (210).  Like  the  crystals 
previously  described  these  crystals  also  show  a  slight  elongation  in 
the  direction  of  the  clino-axis.  The  average  length  in  this  direction 
is  about  7  millimeters.  In  the  direction  of  the  vertical  axis  a  length 
of  15  millimeters  is  frequently  exhibited.  Fig.  3,  PL  LIII,  illustrates 
these  crystals.  Some  of  the  smaller  crystals  of  this  specimen  are 
hollow  in  the  direction  of  their  length.  A  basal  projection  of  all  the 
forms  observed  upon  both  specimens  is  given  in  Fig.  4,  PI.  LIV. 

The  following  is  a  list  of  the  forms  observed,  together  with  meas- 
ured and  calculated  angles: 


a 

(100) 

z 

(2oi) 

V 

(230) 

b 

(010) 

h 

(610) 

t*> 

(120) 

c 

(001) 

I 

(210) 

8 

(250) 

<! 

(on) 

13 

(32°) 

f 

(212) 

r    (012)  w  (430)  e      (In) 

y  (032)  77    (650)  n     (2i2) 

x  (Toi)  m  (no) 


i6o 


FrELD  Columbian  Museum — Geology,  Vol.  III. 


Observed 

Calculated 

b 

A 

h 

= 

(oio' 

A 

(610) 

= 

77° 

48 

'         77° 

3*' 

b 

A 

I 

= 

(oio 

)  A 

(210) 

= 

56° 

37 

'    56° 

38K' 

b 

A 

0 

= 

(oio 

)  A 

(32°) 

= 

480 

38 

480 

44' 

b 

A 

w 

= 

(oio 

)  A 

(43°) 

= 

45° 

21 

45° 

22' 

b 

A 

V 

= 

(oio 

)  A 

(650) 

— 

42° 

13 

42° 

2l' 

b 

A 

m 

= 

(oio" 

A 

(no) 

= 

37° 

12' 

37° 

13' 

b 

A 

V 

= 

(oio" 

A 

(230) 

= 

260 

52' 

260 

51' 

b 

A 

P 

= 

(oio^ 

A 

(120) 

= 

20° 

47' 

20° 

48' 

b 

A 

8 

= 

(oio 

)  A 

(250) 

= 

17° 

10 

160 

54' 

c 

A 

r 

= 

(ooi 

)  A 

(012) 

= 

24° 

3 

'    230 

58' 

c 

A 

q 

= 

(001 

)  A 

(011) 

= 

4i° 

32 

4i° 

39' 

c 

A 

y 

= 

(ooi 

)  A 

(032) 

= 

53° 

5 

53° 

8' 

c 

A 

f 

= 

(ooi 

)  A 

(212) 

= 

30° 

56 

3°° 

5i' 

c 

A 

n 

= 

(ooi 

)  A 

(212) 

= 

46° 

J3' 

460 

20' 

b 

A 

e 

= 

(oio 

>  A 

(In) 

= 

47° 

3' 

46° 

59' 

b 

A 

n 

= 

(oio 

)  A 

(212) 

= 

65° 

5 

64° 

59' 

b 

A 

X 

= 

(oio" 

)  A 

(Toi) 

= 

oo° 

20' 

9o° 

oo' 

c 

A 

z 

= 

(ooi 

)  A 

(2oi) 

= 

690 

36' 

69° 

53' 

RUTILE 
JEQUITINHONHA   RIVER,   BRAZIL 

FIG.  I.  PLATE  LI 

Several  crystals  of  rutile  of  an  interesting  habit  were  presented  to 
one  of  the  authors  by  Olaf  E.  Ray,  Esq.,  of  the  Chicago  Brazilian 
Diamond  Company.  The  crystals  were  obtained  by  Mr.  Ray  from 
sands  washed  for  diamonds  on  the  Jequitinhonha  River  near  Diam- 
antina,  Brazil.  The  crystals  are  twins  ranging  from  9  mm.  to  13 
mm.  in  length  and  8  to- 10  mm.  in  width  in  the  direction  of  one 
lateral  axis  while  in  the  direction  of  the  other  lateral  axis  their  thick- 
ness is  only  2  to  3  mm.  The  crystals  have  the  typical  brownish- 
black  color  of  rutile  and  are  practically  opaque  but  occasionally  are 
dark-red  by  transmitted  light.  The  planes  are  splendent.  Exami- 
nation by  the  reflecting  goniometer  shows  the  crystals  to  be 
made  up  of  the  ditetragonal  prism  h  (210)  and  the  pyramid  of 
the  second  order  e  (101).  The  development  of  the  planes  of  the 
pyramid  is  not  uniform,  two  planes  always  being  larger  than 
the  other  two.  The  twinning  plane  is  v  (301).  The  prismatic  planes 
are  frequently  striated  parallel  to  the  prismatic  edges  and  hence 


Dec,  1908.  Mineralogical  Notes  «  161 

usually  give  successive  signals.  Fig.  1,  PI.  LI,  exhibits  the  usual 
development.  In  addition  it  may  be  noted  that  one  individual  of 
the  twin  usually  shows  a  tendency  to  grow  by  the  other,  suggesting 
a  penetration  twin;  but  the  growth  is  never  extended  far.  Deter- 
mination of  the  specific  gravity  gave  4.284  The  forms  and  measure- 
ments observed  are  as  follows: 


h  (210)  e  (101) 


h 

A 

h'        - 

(210) 

A 

(120) 

h 

A 

hvii    = 

(210) 

A 

(2I0) 

e 

A 

e"      = 

(101) 

A 

(Toi) 

c 

A 

e  of  twin 

Observed  Calculated 

36°  13'  360  52' 

520  10'  530     8' 

65°  3»'  650  35' 

540  12'  54°  42' 


SPHALERITE 

TUCKAHOE,  MISSOURI 

As  is  well  known,  sphalerite  occurs  in  the  Joplin  district  in  the 
form  of  small  crystals  in  clay,  and  occasionally  in  sufficient  abundance 
to  be  used  as  an  ore.  Mr.  James  Roach  of  Tuckahoe,  Missouri,  who 
mines  ore  of  this  character,  kindly  selected  about  25  of  the  best  crystals 
and  presented  them  to  the  Museum,  Mus.  No.  M  6382.  The  crystals 
are  of  interest  as  showing  an  unusual  habit  for  sphalerite  and  one 
which  is  in  some  respects  difficult  of  interpretation.  The  crystals 
range  from  5  to  20  mm.  in  diameter  and  are  of  a  generally 
tetrahedral  form.  In  color  some,  generally  the  smaller  ones,  are 
reddish-brown  and  nearly  transparent,  but  the  majority  are  dark- 
colored  and  opaque.  The  development  of  the  crystal  planes  varies 
from  almost  indiscriminate  rounding  to  well-defined.  All  the  crystals 
however,  as  stated,  show  a  general  tetrahedral  form.  Now  and  then 
apparent  re-entrant  angles  are  to  be  seen,  which  suggest  that  the 
crystals  are  probably  twins ;  but  on  breaking  the  crystals  no  differ- 
ences of  cleavage  can  be  observed  to  confirm  this  supposition.  As  a 
rule  the  crystals  are  made  up  of  only  fifteen  planes,  but  occasionally 
eighteen  can  be  observed.  None  of  the  planes  are  sufficiently  brilliant 
to  give  measurements  with  the  reflecting  goniometer,  but  the  crystals 
are  of  such  size  that  satisfactory  results  can  be  obtained  with  the 
contact  goniometer.  By  study  of  the  crystals  in  this  manner  the 
presence  of  the  tetrahedron  and  cube  can  be  definitely  and  satisfac- 
torily determined.     These  forms  are  always  present  in  their  full  num- 


162 


Field  Columbian  Museum  —  Geology,  Vol.  III. 


Fig.  5.    Sphalerite. 


ber  of  planes.  Moreover,  the  character  of  their  planes  is  distinctive, 
the  tetrahedrons  being  always  more  or  less  rough  from  etching  and  pit- 
ting and  the  cubical  faces  usually  smooth  and  often  more  brilliant 

than  the  other  planes.  The  re- 
maining planes  show  an  angular 
measurement  upon  the  cube  and 
tetrahedron  corresponding  to  that 
of  planes  of  the  hemitetragonal 
tristetrahedron  p  (221),  but  the 
full  number  of  planes  of  this  form 
is  never  present.  As  a  rule  a 
single  plane  of  the  form  occurs  in 
three  quadrants  and  two  in  the 
fourth.  One  crystal,  however, 
exhibits  two  planes  of  the  form  in 
each  quadrant.  It  is  of  interest 
to  note  that  in  the  pyrite  de- 
scribed by  Penfield  from  French  Creek,  Pennsylvania  *  a  somewhat 
similar  lack  of  planes  occurs.  Owing  to  the  etched  character  of  the 
tetrahedral  faces  on  the  sphalerite  it  is  probable  that  the  tetrahedron 
present  is  the  positive  one  and  the  tristetrahedron  is  therefore 
to  be  regarded  as  negative.  Fig.  5  illustrates  the  development 
exhibited  by  the  majority  of  the  crystals.  The  crystals  with 
rounded  planes  have  as  a  whole  more  nearly  the  appearance  of 
the  tetragonal  tristetrahedron  than  those  which  are  more  fully 
developed.  The  tristetrahedron  may  therefore  be  regarded  as  in  a 
sense  the  fundamental  form  which  is  modified  in  the  more  fully 
developed  crystals  by  the  cube  and  tetrahedron.  A  list  of  the  forms 
and  angles  follows: 

a  (100)  o   (111)  p   (221) 

Observed  Calculated 

a  a  o  =  (100)  a  (111)  =  550  12' (average  of  11  measurements)  540  44' 
a  A  ?  =  (loo)    a  (221)  =48°  14'  "        "    15  "  48°n/ 

a  a  p  =  (001)  a  (221)  =70°  00'  "       "     6  700  31' 

*  Am.  Jour.  Sci.,  1889  (3).  37,  p.  209. 


Dec,  1908. 


MlXERALOGICAL   NOTES 


163 


VIVIANITE 

SILVER  CITY,   IDAHO 

A  crystal  of  vivianite  of  unusual  size  and  transparency,  Mus.  No 
M  9454,  from  Silver  City,  Idaho,  was  received  from  Maynard  Bixby 
The  crystal,  attached  to  a  group  of  small  quartz 
crystals,  constitutes  the  only  specimen  of  the 
occurrence  known  to  the  writers.  This  crystal 
is  transparent  and  dark-green  in  color  by  trans- 
mitted light  but  by  reflected  light  in  certain 
positions  appears  azure-blue.  It  is  prismatic 
in  habit  and  elongated  both  in  the  direction  of 
the  c  and  b  axes.  Its  length  in  the  direction  of 
the  c  axis  is  3.5  cm.,  in  that  of  the  b  axis  1.7 
cm.,  and  in  that  of  the  a  axis  1.1  cm.  It  is 
completely  developed  except  for  the  termina- 
tions of  one  end  of  the  vertical  axis.  Measure- 
ments made  partly  with  the  reflecting  and 
partly  with  the  contact  goniometer  show  the 
following  forms  and  angles: — 


a  (100),  b  (010),  m  (no),  w  (Toi),  v 


a   a 

m 

= 

(100) 

A    (no) 

a'  a 

w 

= 

(loo) 

A    (Toi) 

b    a 

V 

= 

(010) 

A    (In) 

Fig.  6.     Vivianite 

(in). 

Observed 

Calculated 

36°  3°' 

35°  59' 

56° 

54°  4o' 

58° 

6o°  13' 

The  development  of  the  crystal  is  illustrated  in  the  accompanying 
figure,  Fig.  6. 


Plate  XLV. 

Anglesite. 
eureka,  utah. 

Forms:  a  (100),  b  (010),  c  (001),  m  (110),  «5  (230),  n  (120),  o  (Oil),  r  (112), 
z  (111),  r  (221),  p  (324),  y  (122). 


FIELD  COLUMBIAN  MUSEUM. 


GEOLOGY,  VOL.  III.,  PLATE   XLV. 


LIBRARY 

UNIVERSIIY  Of-  ILLINOIS 

URBANA 


Plate  XLVI. 

Anglesite. 

eureka,  utah. 

Forms:  a  (100),  b  (010),  c  (001),  M  (110),  M  (410),  n  (120),  o  (Oil),  d  (102), 
(104),  z  (111),  p  (324),  y  (122),  /jt  (124). 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,  PLATE  XLVI. 


LIBRARY 

UNIVERSITY  OF  ILLINOIS 

URBANA 


Plate  XLVII. 

Figs.  1-3. 

Barite. 

cartersville,  georgia. 

Forms:  a  (100),  c  (001),  m  (110),  n  (120),  /  (130),  X  (210),  o  (Oil),  z  (111), 
f  (113),  q  (114),  y  (122). 

Figs.  4-5. 
Bertrandite. 
albany,  maine. 
Forms:  a  (100),  b  (010),  c  (001),  m  (110),  /  (130),  /  (203). 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,   PLATE  XLVII. 


LIBRARY 
UNIVERSITY  Of  ILLINOIS 

URBANA 


Plate  XLVIII. 

Fig.  1. 

Calcite. 

crystal  palace  mine,  central  city,  missouri. 

Forms:  e  (0112),  u.  (0533),  M  (4011),  v  (2131). 

Fig.  2. 
Calcite. 
cuban  mine,  joplin,  missouri. 
Forms:  r  (1011),  ,i  (5491),  /;  (5273),  S&\  (5161),  G:  (72S5),  « (1236),  A  (2332). 
The  letters  followed  by  dots  are  Goldschmidt's;  those  without  dots,  Dana's. 


FIELD  COLUMBIAN   MUSEUM. 

GEOLOGY,  VOL.  III. 

PLATE  XLVIII. 

/_*•    //    \             v.- 

/    31   k      y_     \ 

V\ 

\^ ~~" 

\  \     Yv         /^^ 

\  \ v  V  *  / 

v\     \       /           v' 

/?        -/ 

Fig.  i 

1/ & 

Si 

" — >T^^ 

fCc: 

yd?         * 

\  h   yv---^ 

#! 

\a\  a\ 

. 

r 

Fig .2. 

LIBRARY 

UNIVERSITY  OF  ILLINOIS 

URBANA 


Plate  XLIX. 

Fig.  1. 
Calcite. 
bellevue,  ohio. 
Forms:  n  (1123),  a  (4483),  y  (8.8.T6.3).  r  (1011),  /Jt:  (20.11.31.11). 

Fig.  2. 
Calcite. 
blackberry  mine,  joplin,  missouri. 
Forms:  e  (0112),,/  (0221),  M  (4051),  t  (2134),  v  (2131),  E  (4156),  v:  (11.4.15.3). 
The  letters  followed  by  dots  are  Goldschmidt's ;  those  without  dots,  Dana's. 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,  PLATE  XLIX. 


LIBRARY 

UNIVERSITY  Of  ILLINUiS 

URBANA 


Plate  L. 

Fig.  1. 

Leadhillite. 

shultz,  arizona. 

Forms:  t  (112),  /  (101). 

Fig.  2. 

LlNARITE. 
EUREKA,  UTAH. 

Forms:   a  (100),  c  (001),    m  (110),  r  (Oil),  d  (10  0  9),  0  (9.0.10),  *  (302), 
ft  (201),  g  (211),  /  (S23). 

Fig.  3. 

LlNARITE. 
EUREKA,  UTAH. 

Projected  on  the  clinopinacoid. 
Figs.  4-5. 

MlMETlTE. 
EUREKA,  UTAH. 

Forms:  c  (0001),  m  (1010),  x  (1011). 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,   PLATE   L. 


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Plate  LI. 
Fig.  1. 

RUTILE. 
JEQUITINHONHA  RIVER,   BRAZIL. 

Forms:  h  (210),  e  (101). 

OCTAHEDRITE. 

Figs.  2-4. 

JEQUITINHONHA  RIVER,  BRAZIL. 

Forms:  c  (001),  G  (104),  p  (111),  r  (115),  v  (117),  M  (338),  st  (5.1.19). 


FIELD  COLUMBIAN  MUSEUM. 


GEOLOGY,  VOL.  III.,   PLATE  LI. 


LIBRARY 

UNIVERSITY  OF  ILLINOIS 

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Plate  Lll. 

Olivenite. 

tintic  district,  utah. 

Forms:  a  (100),  b  (010),  c  (001),  m  (110),  v  (101),  e  (Oil),  5  (034),  d  (025). 


FIELD  COLUMBIAN    MUSEUM. 


GEOLOGY,  VOL.  III.,  PLATE  Lll. 


LIBRARY 

UNIVERSITY  OF  ILLINOIS 

URBANA 


Plate  LI  1 1. 

Fig.  1. 

Orpiment. 

mercur,  utah. 

Forms:  a  (100),  b  (010),  m  (110),  u  (120)  o  (101),  e  (103),  d  (103),  /  (023) 
v  (343),  v  (121),  9  (149),  k  (123),  «  (133),  •  (243). 

Fig.  2. 

Orpiment. 

mercur,  utah. 

Drawn  with  positive  forms  in  front. 

Fig.  3. 

Orpiment. 

mercur,  utah. 

Basal  projection  of  forms  observed. 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,   PLATE  Llll. 


LIBRARY 

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URBANA 


Plate  LIV. 

Figs.  1-3. 

Realgar. 

mercur,  utah. 

Forms:  a  (100),  b  (010),  c  (001),  q  (Oil),  r  (012),  y  (032),  x  (101),  z  (201), 
fc  (610),  I  (210)  /?  (320),  w  (430),  jj  (650),  m  (110),  v  (230),  p  (120),  d  (250),  /  (212), 
*  (111),  «  (212). 

Fig.  4. 

Realgar. 

mercur,  utah. 

Basal  projection  of  forms  observed. 


FIELD  COLUMBIAN   MUSEUM. 


GEOLOGY,  VOL.  III.,   PLATE  LIV. 


Pig  3 


